Rhubarb growing problems: 5 common issues to avoid

Get the lowdown on these rhubarb growing problems for a healthier and tastier harvest

rhubarb growing in garden
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There are some rhubarb growing problems to look out for if you're tending to these crops. After all, as with any plant, it's always good to get the lowdown on potential issues so you can avoid them in the first place.

Learning how to grow rhubarb is suitable for the most novice of gardeners as it's generally fuss-free. A hardy perennial, it can be planted in the corner of your vegetable garden where it will produce pinkish-green stems for years to come – with the right care, that is.

rhubarb stems

Rhubarb is an easy crop to grow

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Avoid these common rhubarb growing problems for the best chance at success

Considering rhubarb for your kitchen garden? We've rounded up the key rhubarb growing problems to avoid, so you can enjoy this tasty crop in delicious crumbles, pies, and other baked goods.

1. Crown rot

Mulching rhubarb, usually done in spring, helps to keep weeds down and retain moisture in the soil. However, avoid covering the crown – the visible buds at the surface of the soil. If you don't, your plants can succumb to 'crown rot', where the crown literally rots and the surrounding leaves and stems die.

If you spot any affected areas, the RHS suggests you cut them off immediately for disposal.

That's not the only reason to avoid covering the crown. As the Amateur Gardening experts explain, leaving it exposed to frost is important for getting a good crop of stems the following year.

rhubarb growing

Avoid mulching over the crown of your rhubarb

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2. Pest damage

Just like with many other garden plants, slugs and snails can wreak havoc by nibbling holes in rhubarb leaves. Just one night of intrusion can leave your crops in tatters!

Use natural deterrents where possible to keep them away – our guides on how to get rid of slugs and how to get rid of snails have plenty of tips to try.

Remember, although slugs and snails may find rhubarb leaves tasty, they are toxic to humans and should never be eaten.

slugs on rhubarb leaf

Slugs are a common garden pest

(Image credit: James Davidson/Alamy Stock Photo)

3. Rhubarb diseases

If new holes in your rhubarb plants are accompanied by blister-like growths that start off sticky, then your crop may have caught the common fungal disease Ascochyta leaf spot.

'The first indication of Ascochyta leaf spot are many small yellow-green spots that develop on the leaves,' explains the Amateur Gardening experts. 'About a week later, they turn brown with whitish centers surrounded by a red halo.' The area around each spot then begins to die.

'Sometimes the dead tissue of the spots drops out of the leaf and it may 
be assumed, understandably, that the holes have been caused by some insect eating the leaves,' they add.

'Hygiene is your best approach,' the team continues. Grab your best secateurs and remove infected leaves during the growing season to help to reduce the source of disease. 'Stems with infected leaves should be harvested first, as the stems are still safe to eat. At the end of the growing season, after the leaves have died down, remove and dispose of all remaining plant material, burning them or taking them 
to a household waste site.'

picked rhubarb stems on blue bench

By avoiding these common rhubarb growing problems, you can enjoy a healthy harvest

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4. Congested old plants

If your rhubarb plant is five years old or more and producing weaker and thinner stems than before, it's probably time to divide these perennials up.

'Clumps should be divided every five or six years when the plant is dormant in late winter or early spring to invigorate the plant,' says the Amateur Gardening experts. 

'Ideally, use a strong, sharp knife or spade to split the clump into well-budded portions, replanting them at the same depth at which they were previously growing,' says garden expert John Negus. Space the plants about 3ft (90cm) apart, with the crowns exposed, and make sure they're in a sunny, open spot. 'Finish by watering them in and mulching thickly with composted manure,' he says.

The Amateur Gardening experts add: 'It is best not to harvest the stalks at all in the first season after replanting to allow the newly-planted crowns to build up reserves and to establish a strong, healthy root system.'

rhubarb and rhubarb forcing pot

Large rhubarb plants can be divided to give them a boost in vigor

(Image credit: christopher miles/Alamy Stock Photo)

5. Not fertilizing your rhubarb properly

Rhubarb should be planted in soil that's enriched with well-rotted organic matter. As well as this, adding fertilizer will help the crops grow strongly and develop thick stems. However, incorrect feeding is a common mistake when growing rhubarb

You'll need to do so twice annually, but the type you use depends on the season. Use a nitrogen-rich fertilizer for spring and a phosphorus-rich one for fall which will prepare the plants for winter.

Holly Crossley
Acting Deputy Editor

The garden was always a big part of Holly's life growing up, as was the surrounding New Forest where she lived. Her appreciation for the great outdoors has only grown since then. She's been an allotment keeper, a professional gardener, and a botanical illustrator – plants are her passion.