Growing Rhubarb

In practice, rhubarb is almost always planted by dividing rhizomes or as a potted plant. Growing from seed is possible but rarely done, because seedlings take three years or more before they produce a worthwhile crop. With a bought rhizome or young plant, you can harvest the first stalks as early as the second year.

There are two good windows for planting: in autumn, once the foliage has died back, the plant can root in peacefully before spring. Spring, before new growth starts, is also a good time, especially for potted plants. The planting hole should be generous — about 50 cm across — and enriched with well-rotted compost. The buds should sit only about 2 cm below the surface. Firm the soil well afterwards and water thoroughly.

Each plant needs at least one square metre of space, ideally up to two square metres, because rhubarb becomes really sprawling over the years. Growing in a container is possible, but the pot should hold at least 40 to 50 litres. Compact varieties are far better suited for this than the large standard types.

Rhubarb loves a full sun position. It will grow in partial shade too, but you'll get less yield and the stalks won't colour up as nicely. A sheltered spot is an advantage, especially in very sunny locations where evaporation is high.

Rhubarb likes deep, humus-rich soil with good water retention. At the same time, excess water needs to drain away, because waterlogging quickly leads to root rot. Before planting, it's worth clearing the soil thoroughly of perennial weeds — once they get in between the rhizomes, they're very hard to remove. If your soil is heavily compacted, loosen it deeply and improve it with compost.

With rhubarb varieties, the colour of the stalk flesh matters most. Red-fleshed varieties like 'Holsteiner Blut' or 'Canada Red' tend to taste milder and contain less oxalic acid. 'Holsteiner Blut' is a tried-and-tested variety with plenty of sugar and a pleasant flavour, while 'Canada Red' keeps its red colour even when cooked. If you're looking for something special, try 'Frambozen Rood' — its flavour is reminiscent of raspberry and strawberry.

Green-fleshed varieties are often higher yielding but more tart. 'Timperley Early' shoots particularly early and doesn't need peeling. 'Goliath' produces stalks up to a metre long but needs plenty of space to match.

For sensitive stomachs, there are low-oxalic-acid varieties like 'Elmsjuwel' or 'Elmsblitz'. And if you want to extend the season, have a look at 'Livingstone' or 'Glaskins Perpetual'. These varieties can be harvested much longer, right up to the first frost, and also do well in containers.

As a heavy feeder, rhubarb needs plenty of compost. Add well-rotted compost to the planting hole right from the start. In spring before new growth, give it another feed, and after harvesting in June to July, the plant appreciates a generous helping of 5 to 10 litres of compost per plant. In autumn, a mulch layer of manure or compost does it good.

When watering, less often but deeply is the way to go — this encourages the roots to grow downwards. In a container, you'll need to water more frequently but in smaller amounts to avoid waterlogging.

If your rhubarb sends up a flower stalk, twist it out right at the base. Don't cut it — cut surfaces invite rot. Flowering costs the plant a lot of energy that's then missing for stalk production.

Every 7 to 8 years, it's worth dividing the rhizomes in autumn and replanting them in a new spot. This rejuvenates the plant and gives you new plants for the garden at the same time.

Rhubarb is generally a tough plant that rarely causes serious problems when well cared for. The most common pests are aphids, which not only cause direct damage but can also transmit viruses. Checking regularly helps you spot an infestation early. Nettle tea or horsetail brew are proven remedies. Marigolds and pot marigolds as companion plants keep aphids away naturally.

Caterpillars of the dock moth and the rhubarb looper can cause considerable leaf damage. Picking them off by hand or treating with neem products helps here.

Among diseases, viral infections are the most feared — recognisable by white or coloured spots on the leaves. You need to remove affected plants completely and dispose of them in the general waste, not on the compost heap. Root rot caused by Erwinia bacteria and crown rot caused by Phytophthora almost always occur with waterlogging, which shows once again how important good drainage is. Downy mildew and leaf spot disease caused by Ramularia mainly appear when plants are too closely spaced and air circulation is poor.

By the way: you can use rhubarb leaves themselves as a plant protection remedy. A brew made from 500 g of leaves in 3 litres of water helps against black bean aphids and leek moths.