Rhubarb: Bare Roots or Potted Plant Vegetable
How to Plant
Planting Bare Roots in the Garden:
- When selecting a site, keep in mind that rhubarb is a perennial vegetable and the planting bed should not be disturbed. Early soil preparation is essential in order to establish a healthy rhubarb bed. Rhubarb prefers full sun and a good organic well drained soil. In areas with hot summers, some afternoon shade may be advisable.
- Roots received before planting time may be stored in moist soil or sand and set for 2-3 weeks in a cool place until you are ready to plant.
- Plant roots as early as possible in spring as the soil may be worked.
- Set the roots 3-4 feet apart each way and cover with 3-4 inches of fine soil.
- Firm lightly and keep evenly moist.
- Plants emerge in 6-8 weeks.
Planting Seedling Plants in the Garden:
- When selecting a site, keep in mind that rhubarb is a perennial vegetable and the planting bed should not be disturbed. Early soil preparation is essential in order to establish a healthy rhubarb bed. Rhubarb prefers full sun and a good organic well drained soil. In areas with hot summers, some afternoon shade may be advisable.
- Plant in fall when shipment arrives.
- Set plants 3-4 feet apart each way.
- Dig a hole for each plant large enough to amply accommodate the root ball.
- Set plants level with the surrounding soil. Fill with soil to the top of the hole.
- Press soil down firmly with your hand.
- Keep evenly moist.
- Mulch with 2-3 inches of organic matter.
- Plants will go dormant soon after planting in fall. Mark plant locations with a stake before the foliage goes down. Before new growth begins in spring, apply fertilizer to the ground around the stake.
How to Grow
- Keep weeds under control during the growing season. Weeds compete with plants for water, space and nutrients, so control them by either cultivating often or use a mulch to prevent their seeds from germinating. Avoid disturbing the soil around the plants when weeding.
- Keep plants well watered during dry periods to promote rapid, uninterrupted growth. Plants need about 1 inch of rain per week during the growing season. Use a rain gauge to check to see if you need to add water. It’s best to water with a drip or trickle system that delivers water at low pressure at the soil level. If you water with overhead sprinklers, water early in the day so the foliage has time to dry off before evening, to minimize disease problems. Keep the soil moist but not saturated.
- Fertilize in mid-summer.
- If plants develop seed stalks, cut those off at the base; seed production will weaken the plant.
- Monitor for pests and diseases. Check with your local Cooperative Extension Service for pest controls recommended for your area.
Harvest and Preserving Tips
- Begin harvesting rhubarb plants the second year for two weeks. The third year, harvest for 6 weeks. After the third year, harvest until the stalks become thinner.
- Always leave at least one third of the leafstalks on each plant so it does not get weak.
- Remove the leaves from the picked stalks and discard them. NOTE: Do not eat leaves, they are toxic.
- Do not harvest from frozen plants in fall.
- Leafstalks may be eaten raw or cooked.
- In the fourth year, divide plants by 1/3-1/2.
- Rhubarb may be frozen, pickled, dried, made in chutney or jam.
Common Disease Problems
Botrytis: This fungus causes a grey mold on leaves, stems and crowns. It thrives in cool wet weather conditions. Burpee Recommends: Avoid watering at night and getting water on the plant when watering. Make sure plants have good air circulation. Contact your Cooperative Extension Service for fungicide recommendations.
Downy Mildew: This fungus causes whitish grey patches on the undersides and eventually both sides of the leaves. Burpee Recommends: Rotate crops with plants in a different family. Avoid overhead watering. Provide adequate air circulation, do not overcrowd plants. Do not work around plants when they are wet.
Leaf Spot: Several fungus diseases cause circular or angular spots with beige centers and reddish edges. Affected tissue may die and may drop out of the leaves. Burpee Recommends: Remove and destroy affected plant parts and any plant debris. Practice good garden sanitation.
Root and Crown Rots: A number of pathogens cause root rots of seedlings as well as mature roots and crowns. Burpee Recommends: Pull up and discard infected plants. Make sure your soil has excellent drainage. Contact your Cooperative Extension Service for recommendations.
Virus (Various causes): The most characteristic sign of virus is mottling or ring spots on the leaves. Burpee Recommends: Plant disease free roots. Remove affected plants.
Common Pest and Cultural Problems
Aphids: Greenish, red, black or peach colored sucking insects can spread disease as they feed on the undersides of leaves. They leave a sticky residue on foliage that attracts ants. Burpee Recommends: Introduce or attract natural predators into your garden such as lady beetles and wasps which feed on aphids. You can also wash them off with a strong spray, or use an insecticidal soap.
Flea Beetles: These small hopping beetles feed on plant foliage and may spread diseases. Burpee Recommends: Rotate crops with plants in a different plant family. Use floating row covers to prevent damage to young foliage.
Potato Stem Borer: This caterpillar is about 1- ½ inches long and pinkish white. They feed on surrounding weeds, and bore into the stalks of rhubarb. The adult is a moth. Burpee Recommends: Control weeds. Contact your Cooperative Extension Service for recommendations.
Tarnished Plant Bug: These insects cause distorted leaves and flower buds. The adults are about ¼ inch long, oval shaped and flat. They are greenish brown with reddish brown markings on their wings. There is a small but distinct yellow tipped triangle in the center of the back behind the head. Burpee Recommends: Introduce beneficial insects to your garden. Traps are available. Try insecticidal soap.
Slugs: These pests leave large holes in the foliage or eat leaves entirely. They leave a slime trail, feed at night and are mostly a problem in damp weather. Burpee Recommends: Hand pick, at night if possible. You can try attracting the slugs to traps either using cornmeal or beer. For a beer trap, dig a hole in the ground and place a large cup or bowl into the hole; use something that has steep sides so that the slugs can’t crawl back out when they’re finished. Fill the bowl about ¾ of the way full with beer, and let it sit overnight. In the morning, the bowl should be full of drowned slugs that can be dumped out for the birds to eat. For a cornmeal trap, put a tablespoon or two of cornmeal in a jar and put it on its side near the plants. Slugs are attracted to the scent but they cannot digest it and it will kill them. You can also try placing a barrier around your plants of diatomaceous earth or even coffee grounds. They cannot crawl over these.
Rhubarb FAQs
My roots arrived moldy, are they ok? Will it spread to other plants? This is just a surface mold from shipping and may be wiped off before planting. If the roots are firm and not slimy they are good to plant. It will not affect other plants.
I used to grow rhubarb in Wisconsin, can I grow it here in Florida/Southern California? No, this is a perennial vegetable that needs a cold dormant period. It will not thrive in zones 9-10.
Can I eat the leaves or roots? No, all parts of the plant are toxic except the leaf and the stems.
Can I grow rhubarb from seed? Burpee does not offer seed but yes, rhubarb can be grown from seed. It will take several years before you will be able to harvest stalks.
Can I grow rhubarb in containers? We do not recommend growing rhubarb in containers. The large plants tend to be heavy feeders and not to thrive in containers.