What Is an Annual?

The general definition of an annual is a plant that germinates from seed, flowers, sets seed and dies in one season. Then to complicate matters some annual plants are referred to as hardy annuals or half-hardy annuals. Some half-hardy perennials are also grown as annuals.

Like the general definition, a hardy annual is a plant that completes its life cycle in one year. Hardy annuals do not need to be raised indoors. They can easily be sown directly into their garden locations. Hardy annuals can tolerate light frost without injury. Some familiar hardy annuals include calendula, cornflower, annual larkspur and nigella.

Half-hardy annuals also germinate, grow, flower and die in one year. But, they require a longer period of growth to do so. Half-hardy annuals are started indoors 4 to 8 weeks before the last frost date to give them the extra time they need to mature and begin flowering. They are frost tender and must not be planted outdoors until all danger of frost has passed, usually early to mid-May. Most bedding plants grown by gardeners fall into this category.

Half-hardy perennials, such as dahlia, gazania, geranium, gerbera and tuberous begonia are often treated as annuals. Seeds must be sown early (January or February) to obtain blooming plants by summer. Some, like gazania, are treated as half-hardy annuals and are discarded when a hard frost occurs. Others, like geraniums, can be lifted before a frost, repotted or repropagated by cuttings and grown indoors during the winter. Still others, like dahlias and tuberous begonias, are lifted and their root structures stored in a cool but frost -free location.

Gardeners can grow a variety of plants for a single, annual season of enjoyment. However, a deeper look may reveal something more than the typical annual.

Preventing Tomato Diseases

Septoria leaf spot and early blight are common fungal leaf diseases of tomato. Cultural techniques can help reduce the risk of foliar blight outbreaks.

1. Water and fertilize to maintain plants in a vigorous condition.

2. Avoid fluctuations of too much and too little water.

3. Avoid wetting foliage when watering. If overhead irrigation is used, water early in the day so the leaves dry quickly.

4. Do not work with plants when the foliage is wet.

5. Eradicate weeds. Mulching around plants can help reduce weed growth and prevent a certain amount of evaporation.

6. Choose wilt-resistant varieties. Varieties that are resistant to Fusarium and Verticillium usually have the letters "VF" as part of the variety name.

7. At the end of the season, remove as much plant debris as possible and till under remaining debris. This helps reduce the overwinter of tomato pathogens.

Predicting the Harvest Time for Flowering Vegetables

It is often difficult to estimate when vegetable crops will be ready to be harvested. Weather conditions effect growth and development of the crop and can advance or delay maturity. For flowering vegetables, days from flowering provides a fairly accurate determination of harvest time.

Days from Flowering to Maturity (time in days)
Snap bean (7-10)
Sweet corn (15-23 from silking)
Cucumber, slicing (15-18)
Eggplant (2/3 maximum size) 25-40
Muskmelon (42-46)
Pepper, green (45-55)
Summer squash, zucchini (3-4)
Tomato, red (40-50)
Watermelon, large (50-60)
Watermelon, icebox (28-32)

Oak Tatters

An occasional problem of oaks has showed up more often than normal this spring. You may notice oak leaves that have little or no blade surrounding the main veins, resulting in a skeletal appearance more reminiscent of an asparagus leaf than an oak leaf. Frequently, this damage is mistakenly attributed to leaf-chewing insects.

The name given to this phenomenon is "oak tatters." The damage appears to be caused at or before the time of bud break. The cause of oak tatters is not well understood, however. Similar damage to leaves of other tree species in the northeast U.S. has been attributed to insects called pear psyllids, which apparently can damage leaf tissue by feeding on buds. Whether oak tatters is caused by psyllids, by cold injury and/or by some other mechanism remains a mystery.

Like the cold injury described above, however, oak tatters seems to cause no lasting injury to trees. Its appearance in a particular tree during one year does not imply that it will reappear in a subsequent year. Even when it is present, the damage appears to be esthetic rather than fundamental.

Insect Barrier Clothing

Insect-Out, P. O. Box 356, Cortez, CO 81321, phone 970-565-3006, website (www.insectout.com) sells hooded shirts for adults and children, pants, separate hoods and even baby bags made from polyester netting, for protection against mosquitoes, black flies and deer flies without bug sprays. The netting is white, for maximum coolness, except in the face area, where it is black for improved visibility.

Illinois Fresh

The U-Pick Farms season is almost upon us. Get a free listing of Pick Your Own Farms and Roadside Markets by calling us at 773-233-0476. You can also access this information at our Illinois Fresh site at http://www.urbanext.uiuc.edu/fresh/

July 1999
Gardening in July | 50 Plants & Flowers You May Not Want to Eat | Butterflies & Caterpillars in Your Garden | Patch Disease in Lawns | Ode to Violet | Lawn Care Calendar | Bug Bites | Cybergarden Sites | Hort Shorts | Hort Tips | Summer Time is Tea Time | Locally Grown: The Farmers' Market | Summertime Food: Eating in the Street | It's a Wash: Gardener's Hands | Health & Household Tips | Did You Know

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