Often when people think of perennials, they think of flowers. But there are a number of perennial vegetables available as well! They don't grow like your typical annual veggies, and we've got lots of info to share to ensure your success with growing perennials.
Thanks to co-op member Michalina Hunter of Cicada Seeds for putting together this explainer!
What is a perennial plant?
A perennial is a plant that can live for at least three years, sometimes decades. Most common garden vegetables only live for one year (annuals) or two years (biennials) before they flower, die, and require replanting. Perennials just keep on going!
What are the benefits of perennial vegetables?
Perennial vegetables are:
- Less work to grow - plant them once, harvest for years
- Often more nutritious than their annual counterparts
- More resilient to stressors like pests and drought
- Can grow on “marginal” land (wet, dry, salty, shady)
- Low maintenance
- Promote soil health since they don’t require yearly tilling
- Sequester carbon
- Ready to harvest very early and very late
- Support pollinators and other beneficial insects
How to choose varieties
- Hardiness zone: will it survive your winter?
- What do you like to eat?
- Match plants to your site. Do you have lots of sun or shade?
- What else do you know about your site? Is it wet, dry, windy, hot? Does it have compact or thin soils?
- Consider native food plants for your area, many of which are usually perennial.
Seed Starting
Since perennial vegetables have generally undergone less selection than other common vegetables, their seeds can have more "wild" tendencies, such as requiring cold stratification, or germinating erratically over a long period. But with a little knowledge and patience, I'm confident you can grow them from seed! And on the bright side, since many perennial vegetables live for many years, you won't need to do this very often.
Refer to the "Growing Instructions" section at the bottom of each variety listing for specific guidance on starting that variety from seed.
Cold Stratification
Some varieties need a period of damp cold to sprout. The length of time depends on the variety, but usually ranges from 30-60 days.
Maintenance
Once established, perennial vegetables only require occasional maintenance.
Feeding
Most varieties require less nutrients than their annual counterparts due to their large root systems, mycorrhizal associations, and the fact that they haven’t been bred to rely on fertilizers. That said, your plants will likely appreciate some added fertility. What you add depends on your soil and many other factors, but usually I recommend adding a good quality compost. I use several inches of compost as a mulch for new gardens, and apply a thinner layer of compost, straw, or leaves annually to protect and feed the soil. In general, leafy crops need less food, and crops that make tubers, large broccolis, etc require more.
You may also wish to experiment with growing nitrogen-fixing and mineral-accumulating plants alongside your perennial vegetables to help feed them. The book How to Grow Perennial Vegetables by Martin Crawford discusses this in detail.
Weeding
You’ll want to get perennial weeds under control before planting perennial vegetables since you won’t have the opportunity to till every year after planting. An overview of starting new gardens is beyond the scope of this document, but No-Till Growers on Youtube has excellent videos on the subject (specifically this one). I generally recommend some type of sheet mulching method to make new beds or reclaim a weedy garden.
If you have an established garden, I recommend mulching annually or as needed with weed-free compost/straw/leaves for weed suppression. This drastically reduces weed pressure off the bat. Removing weeds before they go to seed really helps to avoid weeding work in the future.
Pruning
Dead flower and seed stalks can be left over winter to support wildlife and beneficial critters, and pruned in early spring to provide nesting habitat for pollinators before they emerge. If you prefer a tidier look, or want to collect seeds, prune stems to varying lengths of 8-24 inches long to allow for different species of insects to nest in them. Use stem tops as mulch or for compost. The Xerces Society has a helpful handout on pruning for wild bees.
Dividing
Many varieties will slowly multiply from the base, such as skirret and perennial leeks. They may also self seed nearby. Eventually your plants can become crowded, and productivity can decline. At this point plants can be dug up, separated, and replanted. I recommend replanting in another spot to prevent disease build up in the soil.
Enjoy your perennial veggies!
Perennial vegetables can be a game-changer for busy gardeners. I hope you have fun playing around with some new-to-you varieties, growing techniques, and recipes!
The benefits to our environment, soil health, and the time savings of perennial vegetables make them a no-brainer addition to any garden or farm.
