Washington State University Extension

Garden Tips

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written by

Marianne C. Ophardt

WSU Extension Faculty

for the Tri-City Herald, Kennewick, WA

I often get asked a wide variety of questions related to horticulture. It’s part of what makes my job so much fun. I’m a person who doesn’t like to “shoot from the hip” so when I don’t know the answer to a question, I take the time to do a little research. I’d prefer to give a correct answer so both the inquisitor and I can learn something. Here are four questions that I received in recent weeks…. with answers that I needed to look into.

QUESTION 1: Who is correct, the British or the Americans when it comes to referring to sweet corn as “corn” or “maize”? The British apparently use “maize” to refer to what we call “corn”.

The name “corn” is an old Anglo-Saxon word used as a general term to refer to any kind of cereal grain, but sometimes has been used to refer to wheat. In Australia, the use of “corn” is restricted primarily to sweet corn. In England “maize” is used to refer to sweet corn. In most other English speaking countries “corn” is not used as a general term to refer to what we call sweet corn, pop corn, or field corn. The word “maize” is used as a general term to refer to them. “Maize” is a native American word that is used more universally to refer to what we know in this country as corn.

This points out the difficulty in using common names to refer to any type of plant from country to country or region to region. What means “corn” in one place means something else in another place. The scientific name of corn is Zea mays L. ssp. mays. There are a number of important agricultural groupings of Zea mays L. subsp. mays including the Saccharata Group (sweet corn), the Everta Group (popcorn), the Indentata Group (dent corn), the Indurata Group (flint corn), and the Amlacea Group (flour corn).

Maize or “corn” is a native American plant. Scientists believe that primitive forms of maize first grew only in the Andes region of Peru. These forms mutated and crossed with other close relatives before and after the Peruvians transported it to Central America. By way of the Central American natives, these new types of maize found their way into what we now identify as the southwestern United States and then to northern and eastern parts of the country.

Maize eventually became a common crop of most Native American tribes. While the sugary characteristic of maize probably arose through mutation a number of times, it was not favored by most tribes. It wasn’t until the arrival of the Europeans in North America that sweet corn became desirable.

Which is right, corn or maize? I’m not sure, but some U.S. gardeners are starting to switch to the term of maize when talking about what the rest of us call corn. It’s less confusing when communicating with gardeners around the world.

QUESTION 2: What is crocosmia? My friend said I should put it in my flower garden.

Crocosmia is a member of the iris family and is native to South Africa. It’s also known by its common name of monbretia. There are different species and cultivars, some with small flowers and others with large flowers produced in multiple spikes from mid summer to autumn. Flower colors range from yellow to orange to red. The leaves are grass-like and similar to those on flowering iris.

These easy-to-grow plants do best in a well drained soil and are very drought tolerant. They require little fertilizer and do well in sunny sites, but might benefit from some shade with our hot summer conditions. Crocosmia flowers open a few each day, from the bottom of the flower stalks to the tip and are excellent as cut flowers.

Crocosmia are perennials and are hardy in USDA Zones 6 to 7. A mulch should be applied for protection from the cold in late fall, especially the first year after planting, In colder areas, they’re only considered semi-hardy and are grown in containers. Croscosmia arise from corms and tend to be fast establishing and multiplying. Some of the older cultivars such as ‘Lucifer’have been known to become too crowded within a year of planting and fail to flower the second year due to overcrowding.

Cultivars include ‘Meteor’ with small yellow flowers tinged with orange; ‘Red King’ small red flowers with orange-yellow centers;

Emily McKenzie

with large orange flowers; ‘Lucifer’ with large tomato red flowers; ‘Jenny Bloom’ a hybrid with orange buds that open into golden-yellow flowers; ‘Solfaterre’ a hybrid with chocolate brown leaves and apricot yellow flowers that is slower to multiply than other cultivars; and ‘Star of the East’ a hybrid with large bright orange flowers with starry centers of cream and maroon. This plant spreads more slowly than older cultivars.

QUESTION 3: When should I prune my hibiscus?

Do you have a rose-of-Sharon shrub or hardy hibiscus? Rose-of- Sharon (Hibiscus syriacus), a hardy shrub, is pruned in late winter or early spring before new growth begins. Prune out spindly canes and one-third of the oldest growth. The rose-of-Sharon blooms in the summer on new wood.

Hardy hibiscus (Hibiscus moscheutos) usually die back to the ground in the winter and are treated like a flowering perennial. After the tops die back in late fall or winter, trim the plant back to about twelve to eight inches above the ground. When new growth begins in the spring, you can encourage branching by pinching the stems back early in the growing season. While the rose-of-Sharon is a tall shrub, growing from six to eight feet tall, the various cultivars of the hardy hibiscus range in size from two to eight feet tall and two to six feet wide.

QUESTION 4: Is there something wrong with my sycamore tree? Lots of big pieces of bark came off of the trunk and main branches early in the summer. What’s up?

It’s natural for trees to shed bark as they grow, but usually the amount is very small and goes unnoticed. However, certain types of trees such as sycamore, London plane, and silver maple slough off their bark in larger pieces. Some years this shedding is particularly heavy and causes concern… and extra work cleaning it up. There is no need to worry if the bark only uncovers more bark beneath and not bare wood. With sycamore, the patch of bark underlying the shed portion is bright to olive green that later turns to a normal gray color.

Published: 12/25/2004 2:09 PM


written by

Marianne C. Ophardt

WSU Extension Faculty

for the Tri-City Herald, Kennewick, WA

Apparently, humans like to be scared out of their wits. Just look at all those creepy new television shows and the horror movies that are produced every year. Our imaginations are fertile fields for the strange, scary, and seemingly unexplainable. So it’s no wonder that when bizarre things show up in the garden , we can come up with some pretty creative explanations. Really odd things do pop up in the garden now and again, but they can be explained. Let’s talk about a two”weird” manifestations that showed up in local gardens this year and discuss the science behind them.

The most recent problem that presented itself was a plant disease in zinnias. The symptoms noticed by gardeners were weirdly deformed flowers with leaves and other flower parts popping out of the flowers. Those not familiar with the disease might think the cause was exposure to chemicals or genetic tinkering. They do look quite odd, but the real cause is a bacteria-like disease called aster yellows.

Aster yellows is a phytoplasma disease. It’s spread from plant to plant via leafhoppers. Once a “clean” leafhopper feeds on an infected plant it picks up the disease in its salivary glands and then transmits it to the other plants that it feeds on after that. That leafhopper carries the disease for the rest of its life. Generally, the disease shows up more in years where the summer weather is cool and wet, because these conditions are favorable to leafhopper populations. Hot, dry weather is not favorable to leafhoppers or the development of aster yellows disease.

This year the aster yellows has appeared in zinnias from at least two local gardens, but I have also seen it on coneflower in other years. Aster yellows can infect over 300 species of plants. Of most interest to gardeners are asters, coneflowers, coreopsis, chrysanthemum, nasturtium, zinnia, marigold, chrysanthemum, petunia, snapdragon, lettuce, carrot, beets, tomato, potato, pumpkin and onion. This disease generally causes malformed growth and color changes in plant parts. Usually the leaves will turn yellowish with the veins remaining green… the reason for the “yellow” part of the diseases’s name. Infected plants grow more slowly and leaves may become stunted, narrower, or curled. On some plants like zinnia and coneflower, the flowers may be greenish and the flower centers may become enlarged with breakouts of tufts of deformed growth. On carrots, the roots become bitter and “hairy” or covered with little roots.

There is no cure for disease. Once infected, plants should be removed. That’s not too upsetting when annual flowers, like zinnia or petunias, are infected, but it’s much more heartbreaking for gardeners when a large perennial, like coneflower, falls victim.

There is also no simple control for aster yellows. It’s brought to the plants by infected leafhoppers which migrate to this area each year from their winter homes along the Gulf of Mexico. To prevent the leafhoppers from infecting plants in the vegetable garden, row cover fabric can be utilized early in the season. Some commercial vegetable growers also use shiny silvery mulches to deter leafhopper feeding. It’s also important to remove weeds from around vegetable and flower gardens. That’s because susceptible weedy hosts, like dandelion and plantain, can act as reservoirs for the disease and increase the spread of aster yellows in your garden.

Not that long ago, aster yellows and other phytoplasma diseases were thought to be caused by viruses. In 1967, new technology via the electron microscope allowed scientists to determine that the organism was not a virus, but resembled mycoplasmas found in animals and humans. They were then called “mycoplasma-like” diseases. More study revealed that they were unique organisms that more closely resembled bacteria. In 1994, they were given the new name of “phytoplasma”. There are over 300 distinctly different phytoplasma diseases. These include aster yellows, peach X-disease, ash yellows, elm yellows, and a long list of cherry diseases. Fasciation on woody plants that was once thought to be a genetic aberration is now believed to be caused by a phytoplasma. If you’re like me and find all this fascinating, you can find out more information about phytoplasma diseases by going to

At this site you can find “Diseases Caused by Phytoplasmas, Ruth Welliver, Plant Pathology Circular No. 82, Department of Pennsylvania Department of Agriculture, Bureau of Plant Industry, Spring 1999.”

Corn smut is another weird looking problem that showed up on corn in a number of vegetable gardens this summer. Instead of developing normally, large gray tumors or galls grew out of the ears. These galls started out small, but grew bigger and bigger. The greenish to silvery-gray outer covering on the galls later dried and split open, releasing a mass of black to olive green powdery spores. If you don ‘t know what it is, the appearance of corn smut can be quite worrisome.

Corn smut is a fungus, Ustilago zeae, that is spread by spores. In some areas of commercial sweet corn production, as much of 20 per cent of the corn crop can be ruined by the disease. It infects sweet, pop, and dent corn, but

Golden Jubilee


Super Sweet Jubilee

are particularly susceptible.

Spores are spread by wind and in manure from cattle fed with infected corn stalks. As corn begins to mature and form ears, it’s less susceptible to infection, but injury from hail, detasseling, or corn earworms all provide a way of infection and can increase the chance of the disease. Weather and growing conditions also influence the chance of infection. High temperatures and high soil moisture both contribute to higher levels of infection. Because of these influences, earlier (May) plantings of corn are less likely to be infected than those planted later (June).

Control of corn smut involves several cultural practices. First, if corn smut has been a problem in area gardens, it’s good to plant smut resistant varieties such as








, ‘Apache’, ‘Aztec’, ‘Comanche’, ‘Sweet Sue’, ‘Bellringer’, ‘Golden Security’, ‘Merit’, ‘Calumet’, ‘Capitan’, ‘Golden Gleam’, ‘Wintergreen’, ‘Midway’, ‘Pacer’, ‘Bravo’, and ‘Gold Cup’.

It’s very important to remove and dispose of corn smut galls before they burst open and release their spores. Removal must be practiced over a wide area for two or more years, since the spores can persist for two to three years. Perseverence will pay off over time, if all gardeners in the area practice gall removal. It’s also a good idea to follow long crop rotations of three years or more. In the fall, you also need to remove and dispose of diseased plants. Don’t put them in the compost.

If all else fails, you can eat the corn smut galls. Corn smut is a delicacy called “cuitlacoche” in Mexico. The galls are harvested and cooked before they’re mature. I’m told they taste like mushrooms. After all, they are a fungus.

Published: 10/21/2005 11:37 AM



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