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Local Evergreens Turning Brown and Dying

GARDEN TIPS – written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA Written June 11, 2015

Several weeks ago I noted that a number of our local landscape plants were showing signs of problems related to last year’s hot summer and other extraordinary weather events. Now hot weather has arrived much too early and local pines, arborvitae, juniper, and other evergreens are “dropping like flies” causing shock and dismay. Both old mature trees planted 20 years ago or more and younger ones planted less than five years ago are turning brown and dying.

There are a number of factors that have led to this widespread browning and dieback of local evergreens. One is the watering habit of many tree owners. Despite me frequently urging owners to deep water trees and shrubs weekly during hot weather, few actually do this. Instead they rely on lawn watering during the growing season to meet the needs of their trees. This is typically very shallow watering and has subjected a number of trees to years of chronic drought stress. The cumulative effect of this stress has weakened the trees and made them more vulnerable to the weather extremes we experienced last year.

Past winter drought stress is another likely factor in evergreen dieback. While this past winter was fairly “wet” for us, in recent years the winter weather has been mild with little precipitation. That is why I also urge tree owners to take on the burdensome task of deep watering trees, especially evergreens, in October before irrigation water is turned off and monthly during dry, mild winter weather. Again, few do this resulting in additional drought stress.

At this point we might assume that last summer’s heat was the proverbial “straw that broke the came’s back,” but other factors could be contributing to the current dieback problem.

1. Girdling roots restrict the uptake of water. They are caused by a failure to adequately loosen and spread the roots at planting time.

2. In addition to loosening roots at planting time, proper planting techniques are important. Planting too deeply smothers the roots. Leaving plastic pots, biodegradable containers, and even treated burlap around the roots can delay or restrict root growth out of the original root ball.

3. In many landscapes, soil becomes compacted from lawn use or was compacted during home construction. Soil compaction prevents air and water from getting to the roots.

4. Sandy soils and shallow soils are not capable of retaining as much water as heavier or deeper soils, limiting the availability of soil moisture.

5. Physical damage to tree trunks from weed trimmers or mowers impedes the transport of water from the roots to the top of the tree, causing water stress in the top of the tree.

6. I am a strong advocate of mulches, but rock mulches and close proximity to concrete walls put additional heat stress on a tree and increase its need for water. Bark or wood chip mulches are recommended, but when applied in layers thicker than 3-4 inches, they restrict air and water movement.

The are many lessons to be learned from our current situation, but deep watering and keeping our trees and shrubs in good health is one of the most important. There is no one cause for the widespread browning and dieback of local evergreens, but the primary factors are watering, weather, and root problems.

Next week I’ll talk about wood boring insects that are exacerbating the dieback problem by attacking stressed trees and quickening their demise.

The Results of Last Year’s Abnormal Weather

GARDEN TIPS – written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA Written May 21, 2015

I wondered what the repercussions would be from our record breaking hottest-summer-on-record last year. Did you know it reached a high of 109 degrees in mid-July?  I knew this heat strained both us and our electric bills, but it also stressed our landscape plants.

One reason that many of our landscape plants are stressed by high temperatures is because they are not well adapted to our climate, growing better in more temperate regions with higher humidity, like conditions found west of the Cascades. Even in normal summers, these plants are subjected to stress, but the high temperatures experienced here last summer were even more burdensome. At the time I worried, knowing that extremely stressed plants are more vulnerable to attack by insect pests and winter injury from cold temperatures.

In addition to heat stress, many trees and shrubs also likely experienced drought stress last summer because the majority of tree owners habitually fail to provide them with adequate water. They rely on lawn watering for irrigating their large trees and shrubs. As I noted last week, large trees and shrubs should receive additional water with deep watering and moistening the soil to a depth of 12 to 18 inches at least once a week during hot weather. With the extremely high temperatures of last summer, the water needs of these plants were even greater.

The severe heat of last summer was followed by an extraordinarily mild, warm October. Nice for us, but woody plants are cued into the oncoming winter by lengthening nights (shortening days) and gradually cooler weather. The extended warm early fall weather delayed plants from “acclimating” or going through the physiological changes that make them resistant to damage from cold temperatures.

This might not have been a significant problem if temperatures had cooled gradually in late fall, but in the middle of November temperatures suddenly dropped from temperatures in the 60s and 70 into the teens. It was obvious that many trees and shrubs were not prepared for severe cold temperatures, because the leaves were frozen on the trees instead of going through the normal process of leaf fall. Because many plants were not fully acclimated, making them ready for winter temperatures, the severe freeze had the potential to damage buds, twigs, and branches.

So what have been the results of this extraordinary sequence of climatic abnormalities?  Here is a list of the plant problems I have seen so far:

– Flowering cherries that were healthy last year failing to produce flowers or leaves is attributed to cold temperature damage and heat stress.

– Dieback on a number of arborvitae is being caused by the flatheaded cedar borer that attacks heat and drought stressed arborvitae, juniper, and cedar.

– Excessive needle drop, dieback and death of mature pines and other needled evergreens is being noted. It looks like many of these trees were already compromised and on the edge of fatal drought stress from shallow watering practices, past winter droughts, compacted soil, restricted roots, or other factors that restricted water uptake. Last summer’s heat appears to have pushed a number of them over the edge.

In addition to twig dieback, some woody plants have been slow to leaf out and have undersized leaves. As the weather warms, I suspect we will see more plants start to fail. All we can do now is provide the plants with the best growing conditions possible, watering correctly, pruning out obviously dead tissues and hoping for a cooler summer and enough water to keep our plants alive.

Helping Landscape and Garden Plants Cope with Drought

GARDEN TIPS – written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA

Written April 2, 2015

With the prospect of limited irrigation water in the coming months, we may have to make agonizing decisions regarding which plants in our yards and gardens to save and which plants to let go. To me, it is like making ASophie=s Choice.@  Before making these difficult decisions becomes a necessity, there are some things we can do to make the most of the water that will be available.

As much as 50 percent or more of the water that is applied to bare soil is lost to the atmosphere through evaporation from the soil. The rate of evaporation increases with increasing air temperatures, solar radiation, and wind. In addition, the lower the humidity, the faster the evaporation. By applying a mulch in our landscape and garden beds we can reduce the amount of soil moisture lost through evaporation by as much as 50 per cent, depending on the type of mulch.

For landscape plants and perennial flower beds, I recommend using shredded bark or wood chip mulches applied on top of bare soil and maintained at a depth of 3-4 inches. Bark and wood chip mulches should not be used in vegetable gardens and annual flower beds because they will become incorporated into the soil. This causes a problem because soil microbes will use the nitrogen in the soil for the decomposition process, thereby tying up the nitrogen and making it unavailable to garden plants.

Where annual crops are grown and the soil is regularly tilled or disturbed, organic mulches that break down more quickly are advisable. I recommend applying well-rotted compost, lawn clippings mixed with compost, or lawn clippings as mulches. Keep in mind that the general recommendation is not to collect lawn clippings, but if you do have them available they can be recycled as a mulch. However, you should never use clippings if they have been treated with an herbicide without waiting the amount of time specified on the product label.

Never apply more than a one-inch layer of fresh grass clippings at one time because they mat down and start to decompose anaerobically, making a gooey mess. Instead, wait until the clippings last applied have dried, and then apply another one-inch or less layer. The clippings can be tilled into the soil at the end of the season, adding organic matter to the soil.

To increase the effectiveness of a grass or compost mulches, place one to two moistened sheets of newspaper on top of the soil, overlapping the sheets as you place them in the garden, and then cover the paper with a layer of mulch. (Without a cover of mulch, the newspaper will easily be blown away by wind.) Do not use glossy color sections of newspaper, as they may contain heavy metals or other chemicals that will contaminate the soil. The newspaper will decay over the growing season and then can be tilled into the soil along with the layer of mulch on top.

Rock mulches are suitable for areas vulnerable to wildfires or non-plant areas, but they should generally be avoided around landscape plants because they are heat sinks. The rocks absorb heat during the day and then radiate that heat back at nighttime, increasing the heat stress and water needs of plants. Light-colored and white rock also reflects light back onto plants compounding


written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA
published- JUNE 13, 2014


I recently took a watercolor class and our instructor, Chris Blevins, taught us that we should view a mistake as an opportunity to take a painting in a different direction. She calls these Aswap-portunities.@ The same goes for gardeners when a landscape plant dies, grows too big for its location, or just does not perform up to expectations. These problems should be looked at as opportunities to do something different.

For example, I had several scraggly aging lavender plants that were crowding my Stella d=Oro dayliliies in my front landscape. They were no longer attractive and I was tired of deadheading them when they were done flowering. I dug them out this spring, giving me space to plant a small landscape rose that will require less attention. My choice was >Oso Easy Cherry Pie.= It has bright roses flowers and shiny green leaves. It needs little pruning, no deadheading, and does not need spraying.

At the other end of the same bed I have Oso Happy Smoothie, another in Proven Winner=s Oso landscape rose series. It is pretty much a perfect rose for the landscape and it is thornless. From late spring to frost it produces hot pink single flowers with white centers. Deadheading and spraying are also not necessary.

I also decided two shrubs in my back yard needed to go. One of these was the >Bloomerang Purple Lilac= that I was so excited about when it first became available. Except for the flowers it was not and attractive plant. I also removed a >Silver Anniversary= abelia that grew well but looked ragged most of the time. Now I have a couple of spots where I can try something new, which is always exciting for a gardener.

My other Aopportunities@ have come from a few flowering perennials that didn’t make it through the winter. I am still looking for the perfect replacements.

Two shrubs that are staying put are also Proven Winner introductions. They are Lo & Behold >Ice Chip= with white flowers and silvery leaves and >Lilac Chip= with lavender-pink blooms and green leaves. They are darling little butterfly bushes that fit right into a shrub or perennial bed. Both >Ice Chip= and >Lilac Chip= have a mounded growth habit growing about two feet tall and two to three feet wide, diminutive compared to many other butterfly bushes.

Both AChips@ have sterile flowers so they are not invasive and deadheading is not needed. These are very carefree shrubs, plus they attract butterflies and hummingbirds. They have no major pest problems and you simply prune them back the back to the ground in late winter.

I am anxious to see what new plant introductions will be available this year and next from plant marketers like Proven Winners, First Editions, Bailey Nurseries, HGTV, and others. I still have a few spots to fill in my landscape and garden. Time to go shopping and take advantage of my Aswap-portunities.@

Published: 6/13/2014 11:42 AM


written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA

I like to keep track of what’s ‘in’ and what’s ‘out’ when it comes to garden trends. Each year garden style setters and marketers reveal the newest garden trends. One of the 2012 trends noted by Better Homes and Garden is the use of dwarf shrubs in today’s smaller gardens and landscapes. This has been made possible by plant breeders who have selected and bred more diminutive versions of yesteryear’s large shrubs.

The passe shrubs were too big for today’s smaller homes and yards. The new ‘mini-me’ shrubs are much smaller and typically have a lot more to offer… longer bloom, prettier flowers, interesting leaf color or texture, compact growth, fall color, or fruit. Here’s just a few that I find exciting.

Thirty years ago many area landscapes were planted with ‘dwarf’ mugo pines. Unfortunately, dwarf is a relative term. If a plant species grows to a height of 15 to 20 feet in height like a mugo pine (Pinus mugo), a dwarf mugo pine (Pinus mugo var mugo) that grows 7 to 8 feet tall qualifies as a dwarf. However, most gardeners were probably thinking a ‘dwarf’ would be much smaller.

Today there are select cultivars of mugo pine that better fit a gardener’s idea of dwarf. The Mops mugo pine grows to a height of 3 feet tall and wide and even smaller are Slowmound and Teeny that both reach a height and width of only 1 to 2 feet.

Forsythia is one of those shrubs that never went out of style because of its bright yellow early spring flowers, but it really was too big for most landscapes, making it a candidate for ugly hedge-type pruning. Today, smaller forsythia are much easier to use in landscapes and don’t require much pruning. In my front landscape I have Gold Tide, a smaller forsythia that reaches a height of 3 feet and a width of 4 feet. Last month it was covered with cheery yellow flowers. What a treat! Even smaller is Show Off™ Sugar Baby, a petite forsythia that reaches a height of only 18 to 30 inches and is covered with flowers in the spring.

The flowering quince is another shrub that joyfully announces spring’s arrival. Most older cultivars are on the large side, reaching heights of 4 to 6 feet, plus they have nasty thorns. I dislike thorny plants and refuse to plant them in my landscape. Proven Winners recently released three flowering quince as part of their Double Take™ Storm series. These twiggy quince grow to three to four feet tall and wide and are both thornless and fruitless. I have one of all three, Orange, Scarlet, and Pink Storm. Their gorgeous intensely colored double flowers resemble a camellia.

One little new shrub I hope to add to my landscape this year is a sweet mockorange called Miniature Snowflake. Mockorange is a very old-fashioned shrub not found in most landscapes today because the older forms are large (12


) with leggy, unkempt growth. Their redeeming feature is the delightfully fragrant white flowers produced in early summer. Miniature Snowflake mockorange is a compact, somewhat rounded shrub that grows 2-3 feet tall and wide. While not remarkable the rest of the season, it produces sweetly scented pretty double white flowers in early summer. I plan to place it near my patio so I can enjoy its fragrance whenever I walk out the door.

Visit your favorite local nurseries to find these and other smaller shrubs that you can easily tuck into your landscape.
Published: 4/20/2012 9:53 AM


written by

Marianne C. Ophardt

WSU Extension Faculty

for the Tri-City Herald, Kennewick, WA

A long mild spring and then BAMM! Hot weather has arrived and here we are trying to help our lawns and landscapes cope with the stress of high temperatures and intense sunlight. Much of the stress to which plants are subjected involves the greater demand they have for water under these hot, sunny conditions. The higher the temperature… the greater the wind… the more intense the sunlight… the greater the demand that most plants have for water. Unfortunately, it’s not as simple as turning up the irrigation a notch or two to compensate for the increased demand. There are often other factors involved… past watering practices, soil conditions, and cultural practices. Let’s review some of the signs of stress that might be showing up in local lawns and landscapes and then talk about how to relieve that strain.


With this sudden onset of hot weather, large general areas of lawn may have suddenly turned brown. The simple answer might be you aren’t putting enough water on your lawn. To check this, run your system as usual. Several hours after watering, check the moisture in your soil in several locations. The soil should be moist to a depth of at least eight inches. The key is not to water on a daily set schedule, such as 15 or 30 minutes every day. Instead, you should water when the soil becomes dry or the grass starts to turn a blue green indicating water stress. It’s much better to water your lawn less frequently, but more deeply to encourage deeper roots. The frequency of watering will depend on the texture of your soil, weather conditions, the depth of the grass roots, and the amount of water your system applies in a set amount of time.

Another problem could be your irrigation system, such as malfunctioning sprinkler heads or a system that isn’t providing adequate coverage with the available water pressure. Check this by placing tin cans (of the same size) out in various locations in the lawn, being sure to place some cans in the brown areas. Run the system for a set period of time to collect water in the cans. Then measure the depth of the water in each can and compare the amounts to determine if there is uneven distribution. Replace sprinkler heads as needed or make adjustments to the system to get even coverage.

If uneven watering isn’t the problem, the cause of the brown areas might be too thick of a thatch layer in the lawn. If thatch dries out, it often resists wetting and water fails to penetrate, even when the amount of water being applied is increased. If you have a dense lawn, check the thickness of the thatch. (Thatch is a layer of undecomposed roots and lower grass stems between the base of the grass plant and the soil surface. It looks a bit like a cocoa mat.) If the thatch layer is thicker than three-quarters inch, you should dethatch your lawn next spring before the middle of April. Right now, you can get water down through the thatch and to the grass roots by thoroughly aerating the lawn with a hollow-tined aerifier. You should also apply a wetting agent. Wetting agents help water penetrate the hydrophobic or water-resisting thatch.


Lawns aren’t the only plants experiencing heat and stress, but it sometimes takes trees, shrubs, and garden plants longer to exhibit the signs. Wilting is a sure sign of severe drought stress, but often the symptoms aren’t quite as dramatic. On trees and shrubs leaf scorch is a common sign of chronic drought stress. Leaf scorch is characterized by areas of discolored or dry tissue along the edges of the leaf or between leaf veins. The discolored areas are usually irregular. Typically, leaf scorch will be more severe on the side of the plant more exposed to sun, heat or prevailing winds. If the drought stress becomes severe or prolonged, entire leaves will die and twigs may begin to dieback.

If a tree or a shrub is located in a lawn, often the irrigation supplied to the lawn is not adequate to provide for the water needs of the larger plants, especially if the lawn is only watered for short periods on a daily basis. Trees and shrubs in lawns and shrub beds should receive a deep watering at least once a week during extremely hot weather. A young, one-year-old shade tree should be given at least 28 gallons of water a week, a two-year-old tree twice as much, and a four to seven-year-old shade tree should be given 225 gallons or more a week during the hot weather. An older, mature tree can need as much as 400 gallons of water a week!

Leaf scorch may also develop on a tree or shrub even if its water needs are being met. Leaf scorch simply tells us that enough water is not reaching the leaves at the top of the plant. This can be due to a lack of water in the soil, but it can also be the result of trunk or root injury, winter injury, poorly developed or restricted roots, shallow soil, compacted soil, vascular disease, or extreme heat stress. It can even be caused by too much water in the soil, which keeps the roots from getting the oxygen that they need and prevents them from functioning properly.

If a tree or shrub develops leaf scorch, you should check all possible causes of the problem. Again, don’t just turn up the irrigation a notch. Check the soil, it should be moist to a depth of 18 to 24 inches. Adjust your watering to supply tree or shrubs needs. Keep in mind that for older, established plants the water absorbing roots will not be at the base, but out at the “dripline” or reach of the branches. Water applied at the base of older trees and shrubs is wasted and can lead to a disease problem called collar rot.

So help your lawns and landscape plants beat the heat by watering correctly and watching for signs of stress.

Published: 7/3/2004 2:21 PM


written by Marianne C. Ophardt WSU Extension Faculty for the Tri-City Herald, Kennewick, WA LANDSCAPE FABRIC: Twenty years ago, many area landscapes were mulched with black plastic and rock mulches. This combination made it particularly tough to grow trees and shrubs successfully. The black plastic didn’t allow for the free movement of water and air into the soil. Plus, the plastic combined with the rock mulches increased soil temperatures and greatly stressed plants. The black plastic didn’t last indefinitely and weeds became a problem again before long. Eventually ‘geotextiles’ came along and started to replace the troublesome and restrictive black plastic. These woven or spun materials allowed for the free movement of air and water. They also were effective in reducing germinating weeds. Today, geotextile landscape fabrics have become the standard in landscaping, but they have not been the ultimate answer to weed management. Landscape fabrics do have some drawbacks. First, they do degrade over time, especially when exposed to sunlight. Ones that are UV resistant will last longer. Usually a top layer of mulch is applied over the fabric, increasing its life and the appearance of a landscape bed. If an organic mulch (my preference) is used on top of the fabric, eventually the mulch starts to decompose and will become colonized by weeds. Weeds are kept out longer if inorganic rock mulches are used… but eventually weeds will show up whether organic or rock mulches are used over the fabric. Removal of weeds in these situations is made difficult because the weeds’ roots grow into the fabric. Also, the roots of landscape plants tend to grow near the soil surface and grow into the fabrics. When the fabric breaks down and removal is desired, plant roots are damaged. While the use of geotextile fabrics can deter weeds for a some time, it’s better not to use them. They don’t provide permanent weed control in permanent landscape situations. Organic mulches, such as shredded bark, coarse compost, or wood chips, are the best choice for managing weeds in home landscape beds. They are attractive, their decomposition nurtures beneficial soil organisms, and their breakdown helps improve the soil. PRUNING PAINT: ‘Wound dressings’ or ‘wound paints.’ have been around for years and have been used by conscientious, caring gardeners trying to keep their plants healthy. It was thought that these wound dressings would stop wood rot and prevent the entrance of decay organisms and boring insects when painted on tree wounds. Unfortunately, the various wound dressing preparations do just the opposite. Wound dressings seal in moisture, actually creating a better environment for the decay organisms. Some of the materials used delay callus formation and the closing of the pruning wounds, increasing the amount of decay that can occur. They can also increase the amount tissue damage at the wound site, increasing the overall injury. Plus, these materials do eventually dry out and crack, making it easy for pathogens to find their way in. The use of wound dressing has not been recommended by tree care professionals and horticulturists for many years. Products containing collagen, pectin, hydrogel, and aloe gel have all been touted in recent years as natural compounds that will enhance tree healing. Unfortunately, there is no evidence that these new materials or the old materials hasten healing or prevent decay. The best way to promote healing of pruning wounds is to make proper pruning cuts and then leave the wound open to light an air. For other physical wounds to trunks, it’s important to make a smooth edge to the wound and leave it open to air and light. There is no good reason to apply a wound dressing or wound paint to pruning cut, trunk injuries, or cracks in the trunk. PHOSPHORUS FERTILIZERS AND FLOWERING: No doubt you have seen specialized fertilizers on the garden store shelf. Some of these are ‘formulated’ to promote flowering of annuals and flowering shrubs, such as roses. Most of the flower enhancing fertilizers contain higher levels of phosphorus. You can probably find a good number of references and web sites that recommend the application of phosphorus fertilizers to promote flowering, but the truth is that extra applications of phosphorus will do no good if there is an adequate level of phosphorus already present in the soil. Most of our local garden soils have adequate levels of phosphorus, especially if someone has applied fertilizers containing phosphorus in the past. Phosphorus does not readily leach out of the soil, as does nitrogen. By applying excess phosphorus you will decrease soil health. By decreasing soil health, you decrease plant health. Weaker plants are more subject to attack from diseases and insects and susceptible to nutrient deficiencies… setting up a greater dependency on chemicals. So don’t add extra phosphorus from flower promoting fertilizers unless you know your soil is deficient in this nutrient. Is your soil deficient in phosphorus? Get a soil test done to find out. LAWN MOWING: Mowing… it’s the most tedious lawn task, but it’s also one of the most important. Mowing at the right height, the right frequency, and the right way go a long way to providing you with a nice looking, healthy lawn that’s able to resist invasion by weeds and attack by pests. Kentucky bluegrass lawns mowed too high will develop thatch more quickly and will lose a nicely manicured look. Mowing too low is even worse than mowing too high. Low mowing decreases the leaf surface area, decreasing the photosynthesis needed for plant growth. This leads to weaker grass plants with shallower, weaker root systems. This makes the grass plants more prone to stress from possible drought and heat stress during the summer. The recommended mowing height for Kentucky bluegrass lawns in our region is 2 to 2.5 inches. Lawns should be mowed often enough so that no more than 1/3 of the leaf blade is removed at any one mowing. ‘Scalping’ the lawn by removing more than 1/3 of the leaf blade will injure and weaken grass plants. If you go away on vacation and the lawn gets away from you, mow first at the highest height you can achieve on the mower. Once those clippings are dry, mow again at the recommended height in a different direction. (However, it would be better to have someone mow in your absence.) For the best looking lawn, mow your lawn in a different direction every one or two mowings. Mow at right angles to the previous mowing. If you always mow in the same direction, the grass will have a tendency to be pushed in that direction and it won’t stand up well. Be sure to keep your mower blade very sharp. Dull blades tear the ends of the grass, which weakens the grass plants by damaging more leaf tissue and leaves a lawn with an off-color, less manicured appearance.

Published: 6/4/2005 1:40 PM


written by Marianne C. Ophardt WSU Extension Faculty for the Tri-City Herald, Kennewick, WA I recently was visiting a new home in our area. The lawn had been installed before the owners bought the house. The grass was most likely installed for the builder by a contractor when the house was completed. Landscaping the front yard, and sometimes the backyard, before a house is purchased has become a common occurrence in many areas of the country. It makes good sense…. a landscaped front yard increases the selling potential of the house and decreases soil erosion from blowing dust or erosion from runoff. However, I’m concerned about the problems that the new home owners might face with their lawns in the near future. When you don’t install your own lawn, you have no control over the soil preparation before installation… and that could definitely come back to haunt efforts to maintain an attractive lawn or even grow trees and shrubs successfully. The problem arises from the compaction of the soil that occurs from construction activities. Heavy equipment, foot traffic, and loads of building materials all contribute to soil compaction. The soil particles in a compacted soil, wether a lighter sandy soil or a heavier loam, are ‘smushed’ together. This increases the density of the soil and impedes both water and air movement. It also decreases water drainage and hinders root growth. Prior to planting the lawn or landscape, soil should be loosened by deep tilling, debris removed, and the surface graded (sloping away from the house) and leveled. Tilling as deep as eight inches or more is best. This reverses the heavy compaction caused by building activities. Too often this tilling isn’t done prior to planting. Later, the unsuspecting homeowners wonder why they have trouble getting trees and shrubs to grow and why their lawn is no longer flourishing. It’s because of the soil compaction. There is little a homeowner can do short of tearing up the entire landscape and starting over. Few are willing to take this drastic measure and I don’t think I would be either. Rule of Thumb: After tilling and leveling, the soil should be loose enough so that when a 160 pound person walks across the area, they will leave about one-half inch footprints. Most of these new home lawns have been installed with sod. The new owners have had no choice about the type and quality of sod used. If they did have a choice, what should they ask for? Good quality sod is dense and relatively uniform. It should not contain weeds, disease, and insect pests. The layer of thatch should be about one-half inch thick. A certain amount of thatch is necessary to allow the sod to be cut and rolled. However, thick layers of thatch (greater than .75 inch) are excessive and quickly lead to thatch problems. Of course you can’t really tell much about the types of grasses used just by looking at the sod. To make sure it’s quality sod, a perspective buyer should also find out what types of grass are in the sod. For our area of eastern Washington, sod that is predominantly a blend of Kentucky bluegrass cultivars is best. There are more than 125 cultivars (varieties) of Kentucky bluegrass. Different blends are best for different parts of the country, based on conditions and the prevalent disease problems. In our region we should look for cultivars resistant to necrotic ring spot, the main destructive disease problem in eastern Washington lawns. To find out which cultivars of Kentucky bluegrass are resistant to necrotic ring spot disease, consult the Oregon State University publication ‘Necrotic Ring Spot on Turf in Oregon’ available free on-line at Some sod producers will also include other types of grasses in the sod. Turf-type perennial rye grass is good for areas that will see a lot of wear and tear from traffic or play. Fine fescue is good for areas that are shady, such as the north side of the house. Some sod is produced with plastic netting below the roots. This helps producers roll up the sod when different types grasses that don’t form a thatch layer are being grown. Sometimes netting is also used when producing Kentucky bluegrass sod. I would recommend against using Kentucky bluegrass sod that has plastic netting. The plastic does not disintegrate and it can hamper the use of power rakes for removal of thatch in the future. One thing I noted in the lawn of the new home I visited, was poor installation techniques. Pieces should fit together tightly with no gaps between pieces. For a nice appearance, pieces should be placed so that the joints are staggered, as with a brick wall. For a more even surface and to prevent drying, any cracks or gaps between pieces should be filled with soil. Now, let’s talk about the trees and shrubs planted in these new home situations. Compacted soil will also make growing them difficult. If the planting holes are only a little bigger than the root balls and the plants are simply ‘plopped’ in the holes, the trees and shrubs may seem to do alright for a while… but they’ll probably start to decline within several years. The decline will be due to restricted root growth from the compacted surrounding soil and poor water drainage out of the hole. If you have inherited a pre-landscaped home and decide to plant more trees and shrubs without tearing up the turf and tilling the entire landscape, be sure to dig big holes. The holes only need to be as deep as the root ball of the plant, but it should be three times as wide as the root ball… or more if possible. Most roots of trees and shrubs grow in the top 12 to 18 inches of soil. Relieving the compaction by digging a wide hole will provide for root growth. Water management will be more difficult for pre-landscaped homes with compacted soil. Water enters the soil more slowly in compacted soils. Some sprinkler systems are set to apply a lot of water in a short amount of time. With compacted soil, much of this water will run off before it has a chance to penetrate. It would be better to run the system for several short sets on the same day, to allow for water penetration. You end up applying the same amount of water, but apply it in smaller doses. For trees and shrubs, soaker hoses drip irrigation allow you to apply water more slowly. My son and his wife bought a pre-landscaped home, front and back yards, in the Seattle area. It will be interesting to see how the trees, shrubs, and lawn perform. I’ll let you know.

Published: 5/28/2005 1:41 PM


written by Marianne C. Ophardt WSU Extension Faculty for the Tri-City Herald, Kennewick, WA Usually we have several more weeks of cool weather before our spring gardening chores have us all bustling about, but spring has arrived early! It’s time to get our ‘crabgrass preventers’ on lawns. It’s also time to be thinking about what we’re going to use for pest control in our yards and gardens now that diazinon is gone. With a severe drought declared for this year, we need to make some choices in our landscape. Lawns: With this early spring weather, comes the need to apply crabgrass preventers, also known as pre-emergent herbicides, to our lawns. These chemicals (benefin, trifluralin, and pendimethalin) prevent the germination of crabgrass seed. They’re applied to lawns when the soil temperature reach about 50 to 55 degrees. That usually happens when forsythia starts dropping its flowers and redbud trees are in full bloom. (Forsythia is the bright yellow-flowering shrub that’s in bloom right now.) To be effective, you must apply the materials before the crabgrass seeds begin to germinate and grow. Germination starts when the soil reaches a temperature of about 60 degrees and usually continues for several weeks. Because of our early spring weather, you may need to consider a second application of crabgrass preventer late in the spring. This is because some of the materials used may dissipate before the end of this long germination period brought on by our very early balmy weather. Some chemicals, such as benefin, have shorter periods of residual activity, others last longer. Check your label to see how long the product should be effective. Crabgrass preventers are useful chemical tools, but there are lawn care practices that can go a long way in helping control a crabgrass problem . Crabgrass needs light to germinate. A dense, healthy lawn discourages crabgrass. The best way is to keep your lawn thick and healthy is through sound management practices, including proper mowing, irrigating, and fertilizing. Finally, before you use a ‘preventer’ chemical make sure the offending weedy grass is actually crabgrass. Many local gardeners apply these chemicals at the right time and then complain about their ineffectiveness. This could be because the material wasn’t applied uniformly or at the correct rate, but it could also be that the ‘crabgrass’ wasn’t crabgrass at all. Frequently, home gardeners think they’re dealing with crabgrass, when they actually have a tough perennial weedy grass, Bermuda grass. This wiry, tough-to-control weedy grass is not effected at all by the preventer chemicals. To be sure you have a crabgrass problem, bring a sample of your problem grass to the Benton County WSU Extension Master Gardener Plant Clinic in Kennewick. No More Diazinon: Because there were concerns about long-term health hazards, especially to children , the use of diazinon by home gardeners has been canceled. As of the end of 2004, diazinon may no longer be sold to home gardeners… although gardeners may use up their existing supplies. That leaves home gardeners with very few materials for controlling of garden pests, especially chewing insects. There is still an older material, malathion, but many gardeners don’t like it because of it’s odor. Carbaryl, also known as Sevin, is also still available for control of chewing insects. Relatively new on the market are spinosad products. Spinosad is a ‘biorational’ pesticide that is derived from metabolites the result from the fermentation process of a particular soil bacterium. Spinosad mainly kills insects through ingestion… eating treated plant tissues. That means it will control chewing insects, such as caterpillars, leaf beetles, and leafminers but it won’t control sucking insects, such as aphids. It kills the insects by overexciting their nervous systems. It is considered an organic pesticide and has limited impact on certain beneficial insects. Spinosad is available to home gardeners in Monterey Garden Insect Spray. Several local specialty farm and garden stores carry it. It’s also available as Bull’s-eye Bioinsecticide through mail order from Spinosad has no offensive odor and it’s of low toxicity to mammals, but it is highly toxic to bees. It can be used on ornamental plants, most tree fruit, lawns, and vegetables for control of caterpillars (worms), thrips, and leaf miners. It does not have a long residual and several re-applications will be needed with certain pests. Drought Tip 2: Making Choices and Getting Ready for Drought Now Some areas of our region will have only a small percentage of the normal amounts of irrigation water available to them this growing season. Gardeners facing these types of restrictions will need to make some choices now about which plants to save and which plants to let go. If you will be getting very little irrigation water, decide now which parts of your landscape you will water regularly and which ones you won’t. Perhaps the most important part of your landscape are the trees. Trees increase in value as they grow older and bigger in size… and increase your property values. Trees should probably be the first in priority when watering this year. Next, would be well-established healthy shrubs that are contributing to the beauty and value of the landscape. Overgrown, pest-ridden, or poorly placed shrubs could be sacrificed. Perhaps next in the hierarchy would be garden areas with flowering perennials, especially those with special, expensive perennials that would be costly to replace. Lowest on the list would be annual bedding plants and vegetable gardens. These are annual plantings that have a relatively high water demand. You may want to forego these plantings for this year. Finally… many lawn grasses can survive with minimal water. Lawns can be allowed to go dormant (turn brown), but can survive the drought if watered two or three times during the growing season.

Published: 3/19/2005 1:45 PM


written by

Marianne C. Ophardt

WSU Extension Faculty

for the Tri-City Herald, Kennewick, WA

For a long time, a beautiful, thick Kentucky bluegrass lawn has been the “blue ribbon” standard for home landscapes. However, in recent years more and more homeowners have started to rail against the high input needs of these lawns. Many are asking the value and need for wide expanses of green lawn. There are concerns about the environment and use of fertilizers and pesticides, worries about limited quantities of water available for irrigation, and frustration over the amount of time it takes to care for the traditional bluegrass lawn. Are there alternatives to this approach? Yes.

One approach suggested by many is to simply reduce the amount of lawn in the landscape and change a large portion of turf areas to low-water-use landscape beds. The landscape beds are designed so plants with different water needs are placed together in zones. The plants are watered with drip irrigation and mulched with an organic mulch. The use of drought tolerant native and well adapted non-native plants is promoted. If designed well, the time and inputs needed to maintain the area is definitely decreased.

Another option would be changing over to a different type of lawn. The Eco-Lawn concept was developed by Tom Cook, Extension Turfgrass Specialist, at Oregon State University. His goal was to develop a “mowable” groundcover that “looked somewhat like grass lawns but required less input than regular lawns.” The resulting commercially available “Eco-Lawn” or “Ecology Lawn” mixes contain perennial ryegrass, common yarrow, white clover, strawberry clover, and English daisy. Cook has also tried sweet alyssum, Roman chamomile, and baby blue eyes in his trials, but they tended not to persist.

Cook has found that these low-input Eco-Lawns do provide a viable alternative to grass lawns, but they look different than the norm and they’re not “intended to produce perfect green lawns.” They’re mainly for individuals that can’t or don’t want the traditional high-input grass lawn. He points out that his research was done in Corvallis, Oregon and that the standard Eco-Lawn mixes may not work well for all parts of the Pacific Northwest. Nichols Garden Nursery in Albany, Oregon sells a “Dryland Ecology Lawn Mix” that may be suitable for our area. It contains perennial ryegrass, fine fescue grass, strawberry and Dutch white clovers, English daisies, Roman Chamomile, yarrow, and baby blue eyes. You can find them at or call 1-800-422-3985.

Sometimes a lawn of buffalograss, Buchloe dactyloides, is suggested as yet another low-maintenance option. Buffalograss is native to the central and southern Great Plains region of our country. It’s a perennial warm-season grass that is low-growing and both heat and drought tolerant. This prairie grass is fine-textured with a gray green color and it’s being used in some parts of the country as an alternative to traditional high maintenance grasses in home lawns, institutional turf, airfields, golf course fairways and roughs, naturalized areas, and along roadsides.

The main advantages to using buffalograss are that it doesn’t require frequent mowing, watering, or fertilization. It tolerates soil compaction and will grow in dry, clay soils. It does best in full sun, has a deep root system, and has few insect or disease problems. Drawbacks include its intolerance of shade, poor growth in sandy soil and poorly drained areas, and its gray green color. Also, as a warm-season grass it’s slow to turn green in the spring and turns brown after the first frost in the fall. WSU Extension does not currently recommend the use of buffalograss for use in Washington because research has indicated that it does not provide satisfactory long-lived turf in either eastern or western Washington.

Published: 7/1/2006 11:13 AM



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