Fall has arrived and most of the garden is empty now. Life has slowed down, but if you’re growing perennial vegetables, your work isn’t finished yet.
I love growing any kind of perennials – plant them once and they come back every year when given the proper care – but perennial vegetables are truly worth growing. What could be better than food you don’t have to replant every year? Even better, most perennials are ready to harvest in the spring, or at least earlier than many other plants.
Here are some tips on how to prepare your perennial vegetables for winter survival.
Globe artichokes can produce for six or seven years with proper care. They need to be protected from frost and are best grown in USDA zones 5 to 7. Most gardeners in colder zones grow them as annuals.
To prepare your artichoke plants for winter, cut the stalks down, leaving about eight to ten inches on the plant. Then gather the remaining stalks and tie them together to hold them upright. This will help protect the crown of the plant. Add four to six inches of compost around the plant base, and layer up to eight inches of straw or chopped leaves on top of the compost.
In very cold weather, pack a cardboard box with straw or chopped leaves and invert it over the plant. The box can be covered with another deep layer of straw or leaves if needed. Remove the box if the weather warms up.
If you live in Zone 8 or above, cut the plants back to ground level and cover with three or four inches of mulch.
In extremely cold areas, you can dig up the root crowns before the weather freezes and store them in a cool basement or garage. Don’t let them freeze while in storage.
Asparagus crowns will produce a spring crop of spears for twenty years or even longer if they are well cared for, so taking the time to prepare them for winter is time well spent.
Leave the ferny stems on your plants as long as the stems are green. When the stalks turn brown and get brittle, usually after the first frost, cut them off at ground level. Because asparagus beetles can overwinter in the cut-off stalks, don’t add them to your compost pile or leave them in the asparagus bed.
Be patient; don’t cut the stalks too early. The process of photosynthesis, when the green stalks gather energy from the sun, strengthens the plants’ crowns for maximum spear production in the spring. Cutting the stalks back too soon will mean less energy in the crowns over the winter and fewer spears in the spring.
However, if you have any female plants that produce red seed berries in the fall, those seed-producing stalks should be cut down before the seeds form. Female plants use their energy to produce seeds instead of to strengthen their crowns, which means fewer spears in the spring. You can purchase male plants or crowns to prevent this.
To protect your asparagus plants from damage from cold temperatures, mulch the bed with organic material such as compost, well-aged manure, straw or chopped leaves before freezing weather or snow hits your garden. This will not only keep the crowns from freezing but will also enrich the soil for good spring growth. In areas with heavy snow you can add up to six inches of mulch.
In spring the new spears will grow right up through the organic material; there is no need to remove the mulch you applied in the fall.
Walking onions are so named because they reproduce on their own, “walking” across the garden bed. The plants produce topset bulbils, usually three or four in a clump. The bulbils become so heavy in late summer that eventually the stalk will bend in half and fall over, with the bulbils resting on the ground where they form new plants.
Also called bunching or Egyptian onions, walking onions are very hardy perennials that require little maintenance and are very prolific. They will grow nearly everywhere, although they prefer full sun and fertile soil.
The bulbils can also be cut from the stalks and planted in a new location in the early fall. Plant them an inch deep and about a foot apart to give them plenty of room to reproduce in the future.
Before cold weather arrives, tuck an inch or so of straw or shredded leaves around your plants. Walking onions are very cold tolerant and should survive a harsh winter and be one of the first plants to come up in the spring.
Horseradish is a perennial plant from the mustard family. It’s a rugged plant that grows best in areas with a cold winter. It seems to handle winter weather well without much care.
In some areas horseradish grows so well it can be invasive and take over the garden. When you harvest this plant in the fall, remove as many of the roots as you can and only replant as many as you need for the next season. Don’t add the roots you’ve dug up to your compost pile to avoid spreading them all over your garden.
Perhaps because it’s used in pie, rhubarb is often thought of as a fruit, but it is actually a perennial vegetable. It has a deep root system and usually survives the winter without much care.
Rhubarb grows best in the colder zones. It needs an extended period of cold below 40°F to produce stems.
The first frost of the season will kill any leaves and stalks that are still on the plant. They will die off naturally and should be removed from the crown. This is a good time to weed the rhubarb patch and scratch up the soil a bit so it will be ready for spring.
After the ground freezes, mulch the plants with several inches of compost or leaves. In areas with severe cold temperatures, add an additional layer of straw.
A small investment of time in the fall will give you a harvest for many years in the future. The time you spend preparing your perennial vegetable plants for winter will be time well spent.