Growing Rhubarb in Ireland
Peter Dowdall, Irish horticulturist and broadcaster, explains how to plant, establish and manage rhubarb in Irish conditions, including soil preparation, the forcing technique for early spring crops, and why the Irish climate suits rhubarb better than most gardeners realise.
Growing rhubarb in Ireland
Rhubarb is one of the most reliable perennial crops you can grow in an Irish garden. It tolerates our climate exceptionally well, asks for very little once established, and produces a generous harvest every spring for a decade or more.
It is also one of the few food crops that genuinely benefits from the cold Irish winter. The frost triggers a dormancy period that produces stronger, earlier growth in spring. Ireland's climate suits rhubarb better than many gardeners realise.
Rhubarb is a perennial that asks very little once it is properly established. Plant it in well-prepared, well-drained ground, give it a generous feed each autumn, keep it clear of weeds, and it will produce reliably every spring without replanting, without starting from scratch, and without the seasonal effort that annual vegetable crops demand. For a busy Irish garden, that combination of low maintenance and reliable return makes rhubarb one of the most practical choices you can make.
What most gardeners do not realise is that rhubarb's performance is almost entirely determined at the planting stage. A crown planted into deep, fertile, well-structured soil in a position with adequate sun will establish strongly and produce well for ten years or more. A crown planted hastily into thin or waterlogged ground will struggle, produce weakly, and be more prone to the crown rot that is rhubarb's most common failure in Irish conditions.
The other thing worth understanding from the outset is that the leaves of rhubarb are poisonous. Only the stalks are edible. This is not a danger in normal use but it is worth being aware of if you have children in the garden, and the leaves should not go into the compost heap in large quantities.
Planting rhubarb in Ireland
Rhubarb is planted from crowns, which are sections of root with at least one bud, or from pot-grown plants available from garden centres in spring. Both work well. Crowns are the traditional method and are typically planted in autumn or late winter. Pot-grown plants can go in from early spring once the ground is workable.
Choose a position with at least four to five hours of sun. Rhubarb will tolerate partial shade but produces thinner, less vigorous stalks in heavy shade. It needs well-drained soil. In Irish conditions, where winter waterlogging is common on heavier soils, this is the most important factor to address before planting. Rhubarb crowns sitting in saturated ground through a wet Irish winter will rot. If your soil holds water, grow rhubarb in a raised bed or on a slight ridge to keep the crown above the water table. The guidance on raised beds in Ireland covers the practical approach in full.
Prepare the ground generously. Dig to at least 30cm and incorporate a substantial amount of well-rotted organic matter. Rhubarb is a heavy feeder and a long-term occupant of the same ground. What you put in at planting will support the plant for years. Understanding your soil before you plant is worth doing: the advice on garden soil in Ireland covers the principles of soil structure and biology that apply directly to preparing a permanent planting area like this. Improving the underlying soil biology at this stage, not just the fertility, produces a more resilient crown that establishes faster and performs more consistently over its productive life.
Build the soil before you plant
NutriChar is a certified organic biochar plant food, made using a patented process that locks nutrients into biochar structure rather than allowing them to wash away. For a long-term perennial like rhubarb, working it into the planting area at preparation stage pays back across the full life of the planting. The improvement in moisture retention and nutrient availability compounds year on year.
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Plant the crown with the bud just at or slightly above soil level
The bud, the reddish growing point, should sit at the surface or just above it. Burying it too deeply encourages crown rot. If in doubt, plant slightly too shallow rather than too deep.
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Space plants at least 90cm apart
Rhubarb is a large plant that spreads considerably. Crowns planted too close will compete and both will underperform. A single well-placed crown in good soil will produce more than most households need.
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Do not harvest in the first year
Allow every stalk to develop fully in the first season so the crown can build strong roots and reserves. A light harvest in the second year is fine. From the third year onwards, harvest freely within the season limits described below.
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Remove flower stalks immediately as they appear
Rhubarb occasionally produces a thick, round flower stalk topped with creamy-white flowers. Remove this as soon as you see it, cutting it off at the base. Allowing the plant to flower diverts energy from stalk production and can weaken the crown significantly.
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Feed generously each autumn
Once the leaves have died back in autumn, top-dress the crown with a generous layer of well-rotted compost or NutriChar. This is the annual feed that sustains the crown's productivity over its long life. Do not skip it.
Which rhubarb varieties work in Ireland
Most rhubarb varieties perform well in Irish conditions. The choice largely comes down to whether you want an early-season variety, a heavier-cropping mid-season variety, or something that produces across a longer window. A combination of two varieties gives the best of both.
Timperley Early
The most popular early variety and one of the best for forcing. Produces slender, pink stalks from late winter under a forcing pot. Well suited to Irish conditions and widely available. Good flavour and reliable cropping.
Victoria
The classic large-stalked variety. Very heavy cropping, with thick stems and a strong flavour. A long-established variety that performs consistently in Irish gardens. Suitable for both cooking and forcing, though Timperley Early is better for the latter.
Champagne
A sweeter, more tender variety with bright pink stalks. Less vigorous than Victoria but the flavour is superior. Worth growing alongside a heavier cropper to extend the usable harvest season into summer.
The rhubarb growing calendar for Ireland
Season by season
Forcing rhubarb for an early harvest
Forcing is the practice of excluding light from a rhubarb crown in midwinter to produce pale, tender, early stems. It is one of the most rewarding things you can do with an established rhubarb plant, giving you a harvest of exceptionally sweet, tender stalks in February or March, weeks before outdoor rhubarb is ready.
The method is straightforward. In December or January, place a large, light-excluding pot over the crown. A traditional terracotta rhubarb forcer with a lid is ideal, but any large bucket, box or container that excludes light will work. The darkness and the warmth trapped under the cover encourages rapid, etiolated growth. Check every week or two. Stems are ready when they reach about 30cm and before the pale yellow leaves begin to open fully.
Forcing rules worth knowing
Only force crowns that have been established for at least two years. Forcing a young or recently planted crown takes too much energy from a plant that has not yet built the reserves to sustain it, and can set the crown back significantly.
Do not force the same crown in consecutive years. Forcing is demanding on the crown's energy reserves. Give a forced crown a full season of unrestricted growth to rebuild before forcing it again. If you want forced rhubarb every year, establish two crowns and alternate which one you force each season.
After forcing, remove the pot and allow the crown to grow normally for the rest of the season. Do not harvest any further stalks from a forced crown that year. The plant needs the summer growth to recover fully.
Harvesting rhubarb
Pull rhubarb stalks rather than cutting them. Grip the stalk firmly near the base and pull downward with a slight twist. This removes the stalk cleanly and leaves no stub to rot and potentially introduce disease into the crown. If a stalk does break off, remove any remaining stub as cleanly as you can.
Harvest stalks when they are at least 30cm long and well coloured. Take no more than half the stalks at any one picking, leaving the remainder to continue feeding the crown through their leaves. A plant that is stripped of all its stalks at once will take significantly longer to recover and produce again.
Stop harvesting by the end of June. The summer growth that follows the harvest period is not just decorative. The large leaves photosynthesise and send energy back down to the crown, rebuilding the reserves that will produce next year's harvest and sustain the plant through another winter. Cutting into this period weakens the crown progressively and reduces the following year's harvest.
What to harvest
- Stalks at least 30cm long and well coloured
- Pull cleanly from the base, do not cut
- Take no more than half the available stalks at one picking
- Discard the leaves, they are not edible
- Stop all harvesting by the end of June
Autumn aftercare
- Once leaves die back, cut foliage to ground level
- Remove all debris from around the crown
- Top-dress generously with well-rotted compost or NutriChar
- Do not dig around established crowns
- Divide overcrowded crowns every five to eight years in autumn
Questions gardeners ask about growing rhubarb in Ireland
My rhubarb produces thin, weak stalks. What is wrong?
Thin stalks are almost always a sign of one of three things: insufficient feeding, a crown that has been over-harvested or harvested too late in the season, or a crown that has become overcrowded and needs dividing. The remedy in most cases is to skip harvesting for a full season, top-dress heavily with well-rotted compost or NutriChar in autumn, and allow the crown to rebuild. If the plant has been in the same position for more than eight years without division, dig and divide it in autumn, replanting the strongest sections into freshly prepared ground.
Can I grow rhubarb in a container?
Rhubarb can be grown in a large container but it is not ideal for the long term. The root system of an established rhubarb crown is extensive and a container restricts it, limiting both the size of the harvest and the longevity of the plant. If you do grow in a container, use the largest one available, ensure excellent drainage, and feed and water more frequently than you would a ground-planted crown. Replace the compost every two to three years or move to ground planting when space allows.
My rhubarb has produced a tall flower stalk. Should I remove it?
Yes, immediately and at the base. The flower stalk is thick and round, quite different in appearance from the edible leaf stalks. Allowing it to develop fully takes substantial energy from the crown and can reduce stalk production for the remainder of that season. Cut it off cleanly at ground level as soon as you notice it. Flowering is more common in older crowns, in plants under stress, and in dry conditions, but it can happen at any stage.
When should I divide an established rhubarb crown?
Divide rhubarb every five to eight years, or when production starts to decline noticeably despite good feeding and management. The best time is autumn, when the plant is dormant. Lift the crown with a fork, taking care not to damage the roots. Split it into sections using a sharp spade, ensuring each section has at least one strong bud. Replant the best sections into freshly prepared ground and compost or discard the older, central material, which tends to be less productive than sections from the outer edge of the crown.
Is rhubarb safe to grow around children and pets?
The stalks are completely safe to eat. The leaves contain oxalic acid in quantities that are toxic if eaten, particularly in large amounts. In a normal garden setting, with children who are not deliberately eating raw leaves, the risk is low. It is worth being aware of it and worth not adding large quantities of rhubarb leaves to a compost heap that might be accessible to animals. In small quantities the leaves are fine in compost and break down without issue.
That is the general picture
But your garden has its own soil, its own drainage and its own growing conditions. Tell Ask Peter what you are working with and get advice tailored to your specific situation.
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