How to Grow Hollyhocks
from Seed in the UK
A complete cottage garden guide — from sowing to those magnificent towering spires that define the very idea of an English summer garden
There are very few plants that conjure the spirit of the English cottage garden quite as powerfully as the hollyhock. Those tall, stately spires — clothed from base to tip in great saucer-shaped flowers in every shade from the palest blush and cream through to the deepest burgundy, almost-black and vivid magenta — have graced cottage walls and garden borders for centuries. They are the very picture of an English summer, and they photograph beautifully.
Hollyhocks have a slight reputation for being short-lived and tricky, which is partially deserved — they are biennials by nature, taking two years to flower from seed, and they can be susceptible to rust. But with the right approach, both of these things are entirely manageable, and the reward — those extraordinary towering spires reaching two metres or more — is more than worth the patience required. This guide will walk you through everything, from sowing your first seed to enjoying years of self-seeding colour.
Quick Facts at a Glance
Plant Type
Biennial / Short-lived Perennial
Sowing Time
May – July for flowers next year
Flowering Months
June – September
Position
Full sun, sheltered
Eventual Height
150–250cm
Difficulty Rating
3 out of 5 — Moderate
Understanding Hollyhocks
Before you sow, it helps enormously to understand what hollyhocks actually are — because their biennial nature is the single most important thing to grasp about growing them successfully.
Biennial — What Does This Mean?
A biennial plant completes its life cycle over two years. In year one it germinates, grows and establishes a strong root system and a rosette of leaves — but produces no flowers. In year two it puts all its energy into producing that magnificent flowering spike, sets seed, and then typically dies. This is why hollyhocks sown this spring will flower next summer, not this one. Once you understand and accept this, everything else falls into place.
Annual Varieties — A Quicker Alternative
Some modern hollyhock varieties — particularly the Majolica Mix and certain Summer Carnival types — have been bred to flower in their first year when sown early indoors in late winter (January or February). These are worth considering if you want flowers the same year. However, the traditional biennial types are generally considered more vigorous, taller, and more reliably perennial — self-seeding year after year once established. Both are excellent; it depends on your patience and your plans.
Short-Lived Perennial
In practice, many hollyhocks behave as short-lived perennials rather than strict biennials — flowering for two, three or even more years before declining. And because they self-seed so freely, a well-established colony will perpetuate itself indefinitely, with new seedlings constantly replacing aging plants. Once you have hollyhocks settled in a spot they like, you may barely need to sow again.
When & How to Sow
The sowing window for hollyhocks is broader and more forgiving than many people realise. The key is to sow in time for plants to establish well before their first winter — after which they'll overwinter as a leafy rosette and flower the following summer.
Main Sowing Window — May to July
Sowing between May and July gives hollyhock seedlings enough time to develop a strong root system and healthy rosette of leaves before the cold arrives. Earlier sowings (May or June) give slightly more time and produce the most robust plants. July is the latest practical sowing date in most of the UK — plants sown in August or later may not establish sufficiently before winter.
Early Indoor Sowing for Same-Year Flowers — January to February
For annual varieties specifically, sow indoors in January or February in a heated propagator or on a warm windowsill. Pot on, harden off, and plant out after the last frosts. These plants will flower the same summer, though they may be slightly shorter and less vigorous than biennial-grown plants.
Young hollyhock seedlings growing strongly — establishing well now means magnificent spires next summer.
Step by step:
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Choose your method. Hollyhocks can be sown directly outside or started in pots or modules. Direct sowing is simplest and hollyhocks generally transplant reasonably well when young — unlike some flowers with tap roots. Modules or small pots give you more control over placement.
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Prepare the soil or fill your containers. Hollyhocks prefer a well-drained soil in a sunny spot. They are not fussy about fertility — average garden soil is fine. For pot sowing, use a good peat-free multi-purpose compost. Firm gently before sowing.
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Sow at the right depth. Hollyhock seeds are relatively large and flat — easy to handle individually. Sow approximately 6mm deep, one or two seeds per module or in small groups if sowing direct. Cover lightly and water in gently.
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Germinate in warmth. Hollyhocks germinate best at around 18–21°C. A warm windowsill, greenhouse bench or propagator works well. Germination typically takes one to two weeks in warm conditions. Outdoors in summer, germination is usually quick and reliable.
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Thin or prick out. Once seedlings are large enough to handle — two or three sets of true leaves — thin to one per module or prick out into individual 9cm pots. Grow on in a sheltered, bright position.
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Plant out in late summer or early autumn. Once plants are well established — a good root system and several pairs of leaves — plant out into their final position. Late August or September is ideal, giving plants time to settle before winter. Space 45–60cm apart.
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Overwinter as a rosette. Plants will form a flat rosette of leaves that sits close to the ground through winter. This is entirely normal — do not mistake it for failure. The plant is quietly building energy for next year's spectacular display.
Beginner's Reassurance
The most common mistake with hollyhocks is expecting them to flower the same year they're sown, then concluding something has gone wrong. Nothing has gone wrong — your plant is simply doing exactly what it should. Trust the process, overwinter it well, and next summer you will understand completely why people have been growing hollyhocks for centuries.
No Pinching — Staking is the Key Step
Hollyhocks do not benefit from pinching out — they produce a single magnificent central spike and that is precisely their glory. The transformative step for hollyhocks is not pinching but staking, which is genuinely critical for taller varieties and exposed positions.
Those magnificent spires can reach two metres or more — staking early is the single most important thing you can do to protect them.
Hollyhocks growing to 150–250cm are genuinely vulnerable to wind damage, particularly once in full flower and carrying the weight of dozens of blooms. A plant that snaps or collapses in midsummer is heartbreaking — and entirely preventable with a little early attention.
How to Stake Hollyhocks
As soon as the flowering spike begins to rise in late spring — when it's around 30–40cm tall — push a sturdy bamboo cane into the ground beside it, driving it in deep enough to be secure. Tie the stem loosely to the cane at 30cm intervals as it grows, using soft garden twine or stretchy plant ties. For very exposed gardens, two or three canes arranged as a tripod around the plant give excellent stability. Always stake early — it is much harder to stake a tall plant without damaging it than to stake it when young.
The Wall Trick
Hollyhocks have been grown against walls and fences for centuries, and this is not merely aesthetic — a wall provides shelter from wind, reflects warmth, and gives plants something to lean against naturally. If you have a sunny wall or fence, plant hollyhocks close to it and they will need minimal staking. This is the traditional cottage garden approach and it works beautifully.
Growing On Tips
Once established and through their first winter, hollyhocks grow with impressive vigour in their second year. The main tasks through the growing season are watering, managing rust, and encouraging repeat flowering.
The individual hollyhock flowers are extraordinary up close — great tissue-paper petals with a silky sheen.
Watering
Water young plants regularly while establishing and during dry spells in spring. Once in full growth, hollyhocks are remarkably drought-tolerant — their deep root systems seek out moisture effectively. During very hot, dry summers, water deeply at the base every few days. Avoid wetting the foliage as this encourages the rust fungus that hollyhocks are prone to.
Feeding
Hollyhocks are not heavy feeders and perform well in average soil. A single application of a balanced general fertiliser in spring as growth begins is beneficial, particularly in poorer soils. Once flowering begins, a fortnightly high-potash feed — tomato fertiliser works well — encourages continued flower production. Avoid nitrogen-heavy feeds which push leafy growth.
After Flowering
Once the main flowering spike has finished, cut it back to just above a side shoot — the plant will often produce secondary flowering spikes that extend the season usefully into late summer. If you want to save seed or encourage self-seeding, leave a few spikes to set seed fully before cutting back. At the end of the season, cut plants back to the basal rosette and mulch well.
Self-Seeding
One of hollyhocks' greatest qualities is their self-seeding habit. Allow a few seed heads to ripen and scatter naturally and you'll find seedlings appearing nearby the following spring. These self-sown plants are often more vigorous than those you grow from scratch, and over time a happy hollyhock colony will self-perpetuate with very little intervention needed.
Overwintering Established Plants
After flowering, second-year hollyhocks may or may not survive the winter — this is the nature of biennials. To give them the best chance, cut back the spent flowering stems in autumn, leaving the basal rosette of leaves intact, and apply a generous mulch of compost or bark around the crown. In mild winters and sheltered spots many will return; in cold, wet winters some will not. Having self-sown seedlings coming through ensures continuity regardless.
Hollyhock Rust — The Main Challenge
Hollyhock rust (Phragmidium malvacearum) deserves its own section because it is genuinely the most significant challenge in growing hollyhocks well, and knowing how to manage it makes a real difference. Rust appears as orange or brown powdery pustules on the undersides of leaves, often accompanied by yellow patches on the upper surface. Left unchecked it can defoliate plants and significantly weaken them.
How to Manage Rust
Remove and bin (do not compost) any affected leaves as soon as you spot them — this is the single most effective action. Improve airflow around plants by spacing correctly and removing crowded lower leaves. Water at the base, never overhead. A copper-based fungicide applied preventatively from early spring can help in gardens where rust is a persistent problem. Choosing rust-resistant varieties where available is also worthwhile.
Rust in Perspective
It's worth saying that rust, while unsightly, is rarely fatal to an established hollyhock. Plants with rust still flower magnificently, and the flowers themselves are unaffected. Many cottage gardeners manage rust simply by removing the worst-affected lower leaves and accepting a little imperfection on the foliage — the flowers more than compensate. Don't let the possibility of rust put you off growing one of the most beautiful plants in the cottage garden repertoire.
Common Problems & How to Fix Them
| Problem | Likely Cause | What to Do |
|---|---|---|
| No flowers in year one | Normal biennial behaviour | This is completely normal — hollyhocks flower in their second year. Be patient and enjoy the handsome foliage rosette while it establishes. Flowers will come next summer. |
| Hollyhock rust | Fungal disease — orange pustules | Remove affected leaves immediately, water at the base only, improve airflow, apply copper fungicide preventatively. See full rust section above. |
| Slugs & snails | Young plants, moist conditions | Young hollyhock seedlings and the emerging crowns of overwintering plants are vulnerable. Use organic slug pellets, copper tape or beer traps. Established plants are much more resilient. |
| Plants falling over | Insufficient staking, wind damage | Stake early and firmly, before the spike reaches 40cm. Plant against a wall or fence for natural shelter. A collapsed hollyhock can sometimes be carefully re-staked if caught quickly. |
| Poor germination | Old seed, cold conditions, sown too deep | Sow fresh seed in warm conditions (18–21°C). Sow at 6mm depth only. Hollyhock seed viability decreases with age — use seed within two years for best results. |
| Plants die after flowering | Normal biennial lifecycle | Entirely normal for second-year plants. Allow self-seeding to occur for continuity, or save seed to sow fresh plants. Mulching well in autumn gives the best chance of perenniality. |
| Aphids on growing tips | Soft new growth, warm weather | Check the growing tip and flower buds regularly. Remove small colonies by hand or with a blast of water. Encourage natural predators. Avoid high-nitrogen feeds. |
When to Expect Flowers
Hollyhocks sown between May and July will flower the following summer — typically from June through to September, with the peak display usually in July and August. The flowering season for a single plant is around six to eight weeks, though the spire opens gradually from the bottom up, extending the display considerably. Once established, a colony of hollyhocks at various stages of self-seeding will give you flowers reliably every summer with very little intervention.
Annual varieties sown indoors in January or February and planted out after the frosts will typically begin flowering from July of the same year, making them a useful option if you want colour sooner.
High summer and the hollyhocks are at their magnificent peak — a sight that never loses its power to delight.
Planning for Continuous Colour
The classic cottage garden approach is to sow hollyhocks every year — this year's seedlings flowering next year, next year's seedlings the year after, and so on. Combined with the self-seeding habit of established plants, this gives you a continuous, ever-renewing colony of hollyhocks that asks very little of you after the first year or two. Sow a small batch each May or June and you will rarely be without flowers.
Cutting & Using Hollyhocks
Hollyhocks are not conventionally thought of as cut flowers — their stems are tall, their flowers fragile, and they don't last particularly long in a vase. However they do have their uses as a cut flower, and they are magnificent in the garden as a backdrop, a focal point, or grown against a wall or structure where their full height can be appreciated.
For cutting fresh
If you want to cut hollyhocks for a vase, choose stems where several flowers are already open and cut early in the morning. Place immediately into deep water. Individual hollyhock flowers last only a day or two, but as lower blooms fade the buds above continue to open, giving several days of display from a single stem. They make a dramatic statement in a large vase and are wonderful mixed with other tall cottage garden flowers.
Good for Cutting?
Moderately — hollyhocks are not the most practical cut flower given their size and the relatively short life of individual blooms, but they are spectacular in a large arrangement and worth cutting for a special occasion. They are far better appreciated in the garden itself, where their full height and the successive opening of flowers over weeks can be properly enjoyed.
The dried seed heads
Hollyhock seed heads — flat, disc-shaped structures often called "cheeses" because of their resemblance to a wheel of cheese — are charming dried botanical subjects. Allow them to ripen fully on the plant, then cut and dry naturally. They are lovely in dried wreaths and arrangements, and the seeds inside are viable for sowing next year.
For Pollinators
Hollyhocks are outstanding for bees and other pollinators — bumblebees in particular adore them, often disappearing entirely inside the large flowers to collect pollen. Single-flowered varieties are more accessible to pollinators than double forms, though both are visited enthusiastically. A group of hollyhocks in full flower on a warm summer afternoon is one of the most wonderful wildlife spectacles a cottage garden can offer.
Ready to grow your first hollyhocks?
We think every cottage garden deserves hollyhocks — and we've chosen our seeds with real care, selecting varieties that offer exceptional colour, strong performance in the UK climate, and that combination of grandeur and charm that makes hollyhocks so utterly irreplaceable. Whether you're drawn to the softest blush pinks, the deepest almost-black doubles, or a glorious mix of everything in between, we'd love to help you find your perfect hollyhock. Sow this summer, flower next year — it's absolutely worth the wait.
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