Is Broccoli a Perennial Plant?

Broccoli is one of the most popular vegetables grown in home gardens Its green florets and stems are packed with nutrients and have a delicious flavor when cooked right But most gardeners grow broccoli as an annual crop, planting it in spring and harvesting it before summer heat sets in. Once the main head is cut, the plant is usually pulled up and discarded.

But what if you could keep those broccoli plants alive year after year? It turns out, with the right variety and care, broccoli can be grown as a perennial plant.

The Origin of Broccoli

To understand broccoli’s perennial potential, it helps to look at its origins. Broccoli is a cultivar of the plant species Brassica oleracea, which also includes cabbage, cauliflower, Brussels sprouts and kale. These plants all descended from a wild cabbage native to the coasts of southern and western Europe

This wild cabbage had a biennial or short-lived perennial life cycle. It would grow vegetatively the first year then flower set seed and die the second year. But if left unharvested, some plants would continue living for several years, producing smaller side shoots and flowers annually.

Through selection over centuries, farmers developed different vegetable forms of Brassica oleracea optimized for large harvests of leaves, stems or flowering heads in a single season. But the perennial habit remains latent in many varieties.

Choosing the Right Variety

The key to success in growing perennial broccoli is choosing an open-pollinated, heirloom variety that still carries those perennial tendencies. Varieties bred for large, dense, single heads in one season put their energy into that main head and lack the side-shooting nature needed for perennial broccoli.

Some heirloom varieties known to work well include Waltham, Purple Sprouting and Early Purple Sprouting. These varieties produce smaller main heads but abundant side shoots over an extended harvest period.

If you can’t find starts of perennial-suitable broccoli varieties, look for loose-headed leafy types sometimes sold as “walking stick cabbage.” You can also start plants from trustworthy heirloom seeds purchased online or from local seed libraries.

Growing Perennial Broccoli

To get started, plant broccoli in early spring, spacing plants 18-24 inches apart in rows or beds. Fertilize with compost and mulch around plants to retain moisture and suppress weeds. Keep plants consistently watered.

Let the central head develop and harvest it when the florets begin to swell but before yellow flowers emerge. After cutting the main head, allow the plant to continue growing, harvesting side shoots as they reach 3-5 inches long.

In mid to late summer, cut each plant back to 6-8 inches tall. New shoots will emerge from the remaining stem and grow into smaller fall heads. Allow the two strongest stems to grow and lay on the ground. They will form roots at the nodes.

In winter, mulch plants for cold protection. Remove mulch in spring and cut back the two main stems to 6 inches again. The process repeats each year. With this annual pruning and harvesting of side shoots, the original plants can remain productive for many years.

Key Tips for Perennial Broccoli

Here are some key tips to help ensure success with perennial broccoli:

• Choose an heirloom, open-pollinated variety suited for perennial growth. Waltham, Purple Sprouting and Early Purple Sprouting are good options.

• Allow the main head to fully develop before harvesting to build plant energy reserves for regrowth.

• Prevent flowering and seed production by consistently harvesting side shoots. Plants that go to flower and seed will often die afterwards.

• Cut back to low growing points mid to late summer to stimulate new shoot growth into fall and winter.

• Mulch plants in winter to protect from hard freezes if needed in your climate. Remove mulch in spring.

• Prune back to 6 inches each spring before new growth starts to rejuvenate plants.

Benefits of Perennial Broccoli

Growing broccoli as a perennial offers several benefits:

• Extended harvests. Instead of one spring crop, you can harvest fresh broccoli for 9 months or longer from the same plants.

• No need to purchase transplants every year. Re-sprouting established plants saves time and money.

• Less work. With mulching and pruning, perennial broccoli is low maintenance compared to starting a new annual crop each spring.

• Nutrient accumulation. Older plants have extensive root systems that mine nutrients from deep in the soil.

• Drought tolerance. Large roots allow perennial broccoli better access to water.

• Erosion control. The dense, shrub-like growth habit prevents soil erosion.

Potential Challenges

Perennial broccoli does have some potential challenges:

• Lower yields. After the initial spring head, yields of side shoots are lower per plant than typical for standard annual broccoli.

• Susceptibility to pests. Older plants can accumulate pest pressure from cabbage worms, aphids, etc.

• Bolting. Hot weather and drought stress can trigger premature flowering. Timely harvesting and irrigation reduce this.

• Winter survival. In very cold climates, heavy mulching or temporary row covers may be needed to overwinter plants.

• Hybridization. Allowing plants to cross-pollinate can result in offspring poorly suited for perennial growth.

An Intriguing Alternative

For the adventurous gardener, growing broccoli as a perennial plant offers an intriguing alternative to the usual annual broccoli crop. With the right techniques and maintenance, you can enjoy fresh picked broccoli for most of the year from long-lived, low maintenance plants. Give perennial broccoli a try this season and see how it performs in your own garden!