If you want to plant crown vetch, spring is the time to do so. A member of the legume (pea) family, crown vetch is a perennial ground cover. It offers fine-textured foliage in spring and attractive rose-pink to violet flowers from June to August.
It’s a familiar sight along many roadsides. Crown vetch also is planted on slopes, naturalistic areas, spoil banks, and strip-mined areas.
It is generally not often recommended for home planting because of its indeterminate spreading and ragged winter appearance. Varieties include the popular Chemung, which has the best seeding vigor, Penngift, and Emerald.
How Do You Grow Crown Vetch?
Crown vetch spreads by underground stems that may extend 6 feet. One plant can cover four square feet of the ground. It grows quickly and can reach heights of two feet.
Full sun is best for this plant, although it will tolerate light shade. It is almost free of both insects and disease problems and is tolerant of drought and cold.
Crown vetch will grow in infertile soils but will not survive in compacted soil. Adequate ground pH (5.5 to 7.0) is essential. To prepare for propagation, turn the soil much as you would for lawn planting.
How to Care For Crown Vetch
Incorporate fertilizer and lime, if needed, at this point. Use 12 pounds of 5-10-10 fertilizer per 1,000 square feet. You can plant seeds or crowns (individual plants), but do it in the spring; fall plantings usually do not survive.
Crowns obtain a cover faster than seed. For best results, mix crown vetch seed with ryegrass or tall fescue seed. Use one-half pound of crown vetch seed plus three-fourths of a pound of tall fescue or ryegrass per 1,000 square feet.
Mulch the area with straw after seeding. Per acre, use 20 pounds of ryegrass or tall fescue and 15 pounds of crown vetch seed. Add 500 pounds of 5-10-10 fertilizer when you first work the soil.
Do not mow crown vetch until it is well established — two to three years after planting. Then, you can mow it once a year after flowering if necessary.
Fertilize it every three to four years with 10 pounds of 0-20-20 fertilizer per 1,000 square feet.
Crown Vetch Pests
Greenhouse whitefly: The greenhouse whitefly is difficult to control because of its complex life history.
It undergoes five distinct stages, all of which have different tolerance to insecticides. Eggs laid on the bottom of leaves are resistant to all but a very few insecticides.
The egg hatches a crawler that actively searches for a feeding site, usually on the underside of the same leaf.
The crawler does not feed, but because of its mobility, is quite susceptible to contact insecticides. The crawler then becomes a scale. After the scale feeds for some time, it thickens and enters the pupal stage.
Like the egg, the pupal stage is non-feeding and immobile and therefore not susceptible to insecticides. Two to three days after the adult female emerges from the pupa, it begins to lay eggs.
The adults fly from plant to plant, seeking new sites to lay eggs, usually on leaves near the top of the plant. As a whitefly infestation progresses, the five stages (eggs, crawlers, scales, pupae, and adults) tend to exist simultaneously.
Thus, a single insecticide application affects only one stage, leaving the other stages to survive and ultimately reproduce.
Better whitefly control can be achieved if you learn to recognize the first signs of a whitefly infestation and treat at this time.
It is crucial that good coverage of the underside of the leaves is obtained, or control will not be effective.
There are no materials labeled for whitefly control on tomatoes. However, insecticides recommended for aphid control also will help reduce whitefly problems.
Yellow viscous boards offer an alternative to chemical spray. They are often available in garden centers near the pesticides.
The color attracts the insect, and the sticky substance causes them to adhere to the board. This tool can also be used to monitor your garden for small, flying insects.