Cultivation & propagation

Growing rhubarb |

Unlike other garden vegetables, rhubarb is not usually planted from seed. You can purchase rhubarb crowns at most garden centers or nurseries. Or, as gardeners divide their plants every three or four years, opt for divided plants (splits).

Division should be done during dormancy, preferably in early spring. Plants should ideally be over five years old and divisions should contain one large root and at least one bud.

You can also plant rhubarb from seed, but you will wait longer to harvest it and the plant may not have the same characteristics as the parent plant.

Sun – Rhubarb can tolerate partial shade but it prefers full sun, it will produce more stems and will be larger.

Soil Type – Rhubarb is not picky about soil pH and can thrive in acidic, neutral, or alkaline soil. It needs good drainage and prefers soil rich in organic matter, loose and well drained. The roots can easily reach 2-3 feet in height.

Planting – Plant the splinter by placing the underground part of the splinter underground and keeping the buds above ground. Leave between 3 and 4 feet between each plant.

Fertilizer – Every year, in spring, add a good layer of compost or well-ripened manure.

Mulch – Mulch helps keep soils cool and moist like rhubarb likes. So add a good layer (2-4 cm) of hardwood wood shavings or straw all around your rhubarb plant.

My rhubarb is flowering, what should I do? |

When a rhubarb plant flowers, it is called bolting or going to seed. When rhubarb goes to seed, it is completely normal. Rhubarb is doing what plants are supposed to do, which is reproduce, but there are factors that can influence how often a rhubarb plant will flower.

Variety – Some varieties of rhubarb flower more than others, some hardly ever flower. Old varieties tend to flower more often than modern cultivars. Victoria rhubarb, MacDonald rhubarb, and Red Crimson rhubarb are some examples of rhubarb varieties that flower more often.

Maturity – Plants must reach a certain maturity to reproduce by seed. For a rhubarb plant, this maturity occurs a few years (about 3 years) after it is planted. The older a rhubarb plant is, the more likely it is to go to seed.

Heat – Rhubarb plants grow best in cooler temperatures. An unusually warm spring can cause rhubarb to flower. Likewise, heat waves can cause flowering.

Stress – Stress can also force rhubarb to flower. Stress can come in the form of lack of water, infertile soil, pests, fungus, lack of nutrients, or animal damage. Anything that makes the plant feel threatened can cause it to flower. Older plants tend to flower more than younger ones.

How to Stop Rhubarb from Bolting
To stop rhubarb from bolting, you need to determine why it is flowering. If it is flowering because of the variety, you may want to consider purchasing a more modern variety that has been bred to flower less often.

But keep in mind that rhubarb flowering is actually more of a nuisance to us than the plant itself. If you have a rhubarb stand that has been established for several years, you may want to consider dividing it. This essentially delays the plant’s maturity and reduces the amount of rhubarb flowering. If you’re expecting a hot spell, consider mulching around the plant to help keep the roots cool. Also, make sure your rhubarb is as stress-free as possible. Watering during dry spells, fertilizing regularly, and monitoring and treating pests and diseases promptly will significantly reduce the amount of flowering.

Should I Let My Rhubarb Flower?
There’s no harm in letting your rhubarb flower. Since rhubarb is grown for its stems, most gardeners choose to remove the flowers as soon as they appear so the plant can focus its energy on growing leaves. But in reality you don't have to remove the flowers before they bloom, despite popular belief. So enjoy the beauty of its flowers to the fullest, removing the flower stalk only after flowering to prevent bolting. Because it is the bolting (seed production) that can, slightly, weaken the plant.

Also know that if your rhubarb bolts a flower, it does not affect the other stems of the plant. These are still edible and can be used in cooking (although the leaves are still toxic).

Conservation of plants, fragments and roots |

Conservation of seedlings: Seedlings should be planted in the ground as soon as possible. The more they dry out, the lower your chances of getting new plants. If this is not possible, two ways to preserve your plants:

If you have a splinter with leaf(s), keep it in a pot with potting soil or garden soil while waiting to be planted, place the plant in the shade or partial shade if it is very hot.
If you have a leafless splinter, store it in a perforated plastic bag in the refrigerator for a short time, you can add slightly damp sawdust. Before replanting the chilled rhubarb, if the roots are dry soak them in room temperature water for a few hours. When planting the roots, cover the top of the root with no more than 2-3 cm of soil.

Propagation of rhubarb by division |

When: Divide the crowns when the plants are dormant in spring when you see the aerial buds blooming or in the fall. If you do it in the fall, it should be late enough in the season that the leaves don't grow but early enough that the roots develop before the ground freezes.

Frequency: Rhubarb should be divided when the plant begins to develop 20 to 30 or smaller stems instead of 12 to 18 larger stems. This is often around the fifth or sixth year after planting, but can vary depending on variety and growing conditions.

How to divide: No need to dig it up, several videos will tell you to dig up your rhubarb plant to divide it! I tell you, you just have to clear the pallis of the plant to clearly see the buds and using a shovel we cut the plant between the buds into several pieces. You need a minimum of one bud but generally you keep 3 to 5 buds per burst.

Video showing how to divide a rhubarb plant by Christian Sauvé

Conservation: Divided pieces should be planted in the ground as soon as possible. The more they dry out, the lower your chances of getting new plants. If this is not possible, put the pieces in a plastic bag and store them in the refrigerator for a short time, you can add slightly wet sawdust. Before replanting chilled rhubarb, soak the root divisions in room temperature water for several hours or overnight. When planting the roots, cover the top of the root with no more than 2-3 cm of soil.

Planting: Afterwards, simply replant the new splinters in a new location as you do for a new plant, placing the underground part of the splinter underground and keeping them above ground. buds. If you are giving it to someone, you can put the shards in a pot with potting soil or garden soil while waiting to be planted.

When dividing a plant, it sometimes happens that pieces of roots are separated from the plant, keep them, they are future plants. Just place them in the ground in the direction of a carrot (small diameter downwards) under 1 inch of soil. If you can't find the senses of the root, it's no big deal, put the piece horizontally under 1-2 in. of soil, they will produce new plants later.

Propagation of rhubarb by seed |

Rhubarb blooms in summer and produces small greenish-white or red flowers arranged in large clusters. Flowers are designed for pollination by wind. They are also able to perform self-pollination because they have both male and female sexual organs.

Note that to faithfully reproduce a rhubarb plant, the one and only way to do so is to divide an existing healthy plant. Seeds take 7 to 14 days to germinate at 20 to 23°C. The usual lifespan of seeds is approximately 3 years. The seeds are harvested from very ripe and dry flower stalks.

How to Start Rhubarb Seeds

Sow seeds indoors in early spring or 5 to 7 weeks before the last frost date of your area (around mid-March for the Montreal area).
Soak seeds for 2 hours before planting in container.
Sow 1 cm deep in seedling soil.
Keep the compost moist to promote germination.
Transplant into larger pots as needed.
Gradually acclimate plants outdoors when nighttime temperatures are above 0°C.
Plant in the ground once all risk of frost has passed.