What to Plant in Spring: 20 Best Flowers, Vegetables and Shrubs for March, April and May
A complete UK guide to what to plant in spring — covering the best flowers, vegetables, and shrubs for March, April and May, with advice on hardy vs half-hardy plants, seed starting, and hardiness zones.
What to Plant in Spring: The Complete UK Guide to Flowers, Veg & Shrubs
Spring is the busiest planting season of the year — and also the most rewarding. The right plant choices in March, April and May set up your entire garden for a productive, colourful growing season. But spring planting in the UK requires some planning: not everything can go in the ground at once, and the difference between a hardy annual and a half-hardy tender plant can mean the difference between a thriving display and a total loss to late frost.
This guide covers 20 of the best plants to grow in spring — flowers, vegetables, and shrubs — with specific timing advice based on UK climate conditions and hardiness zones.
Understanding Spring Planting Windows in the UK
The UK spans USDA hardiness zones 7–9. London and the South West are the warmest (zone 9), while upland Scotland and the North of England sit at zone 7. Last frost dates range from early March in the mildest coastal areas to late May in exposed upland regions.
As a general rule for most of England and Wales:
- Hardy plants (fully frost-tolerant) — can go in from early March
- Half-hardy plants (tolerates light frost) — plant from late March to mid-April
- Tender plants (no frost tolerance) — wait until after last frost, typically mid-to-late May
Always check local last frost data for your specific area. The Met Office and RHS provide regional guidance.
Flowers to Plant in Spring
1. Sweet Peas (Lathyrus odoratus)
Sweet peas are among the most rewarding spring flowers. Sow seeds outdoors from March in a sunny position at the base of wigwams or trellises. Alternatively, start them indoors in October/November for the largest plants, or in late February for spring planting. Pinch out growing tips when 10cm tall to encourage bushy plants. The more you cut sweet peas, the more they flower — perfect for the vase.
2. Dahlias
Start dahlia tubers in pots indoors from late March/early April, then plant out after last frost in May. Dahlias need a sunny spot, well-drained soil, and sturdy staking. They flower from mid-summer until the first autumn frost, making them one of the longest-performing garden plants. Lift and store tubers in autumn if you’re in a frost-prone area.
3. Sunflowers (Helianthus annuus)
Sow sunflowers directly outdoors from late April, or start indoors in April and plant out in mid-to-late May. They’re fast-growing and largely undemanding — just give them full sun and deep soil for tap root development. Sunflowers attract bees and other pollinators, and the seed heads provide food for birds in autumn.
4. Marigolds (Tagetes)
Marigolds are spring planting workhorses. Sow French marigolds (Tagetes patula) indoors from March and plant out in May, or sow directly from late April. They flower from early summer until frost. Marigolds are invaluable as companion plants — their scent deters whitefly, aphids, and even rabbits. Plant them alongside tomatoes, courgettes, and other vegetables for combined ornamental and pest-control benefits.
5. Cosmos (Cosmos bipinnatus)
Cosmos is one of the easiest half-hardy annuals to grow from seed. Sow indoors from March or direct from late April. The feathery foliage and daisy-like flowers in pink, white and crimson appear from July and continue until October. Cosmos self-seeds freely in sheltered gardens, often appearing the following year without any effort.
6. Nasturtiums (Tropaeolum majus)
Sow nasturtiums directly outdoors from late April — they dislike root disturbance and resent transplanting. They thrive in poor, well-drained soil and full sun; overly rich soil produces leaves at the expense of flowers. Both flowers and leaves are edible, with a peppery flavour. Nasturtiums are excellent companion plants, attracting aphids away from more valuable crops.
You might also find what to plant in summer helpful here.
7. Cornflowers (Centaurea cyanus)
Hardy annual cornflowers can be sown directly from late March. Scatter seeds thinly in a sunny, well-drained spot and thin to 30cm apart. They grow quickly and flower in June/July, then self-seed prolifically. Cornflowers are beneficial insect magnets — the deep blue flowers are particularly attractive to bumblebees.
Vegetables to Plant in Spring
8. Courgettes / Zucchini (Cucurbita pepo)
Courgettes are among the most productive vegetable garden plants. Sow seeds on their sides in small pots indoors in late April and plant out after last frost in late May. Give each plant 1m of space — they spread widely. Pick courgettes when 15–20cm long; leaving them to become marrows reduces subsequent cropping. Courgettes and tomatoes make excellent companion plants, making the most of space in smaller gardens.
9. Tomatoes (Solanum lycopersicum)
Tomatoes need to be started indoors in March or early April — they require a long growing season to crop well in the UK climate. Grow on in a heated propagator until large enough to pot on, then harden off and plant out into grow bags, containers, or borders after last frost. Our tomato care guide covers the full growing process from sowing to harvest, including side-shooting, feeding, and variety selection for UK conditions.
10. Lettuce and Salad Leaves
Lettuce is one of the fastest-growing spring crops. Sow direct outdoors from March (in mild areas) or from April more broadly. Make successional sowings every 2–3 weeks for a continuous harvest. Cut-and-come-again varieties such as ‘Salad Bowl’ and ‘Lollo Rossa’ allow you to harvest outer leaves repeatedly without pulling up the plant. Lettuce bolts (runs to seed) quickly in hot weather — choose bolt-resistant varieties for late spring sowings.
11. Runner and French Beans
Sow runner beans and French beans indoors from late April and plant out after the last frost in late May or early June. Alternatively, sow directly outdoors from mid-May. Both types need support — runner beans require tall canes or wigwams, while French beans can be grown as bush types needing no staking. Begin picking pods regularly as soon as they reach full size to encourage continued cropping.
You might also find what to plant in summer helpful here.
12. Peas (Pisum sativum)
Early and second early pea varieties can be sown directly outdoors from late March. Prepare a shallow trench 5cm deep, scatter seeds every 5cm, and cover. Provide support with twiggy sticks or netting as peas climb via tendrils. Harvest regularly once pods are plump. Mangetout and sugar snap varieties are more forgiving of late harvesting than shelling peas.
13. Beetroot
Beetroot is a reliable and easy spring crop. Sow directly from April in rows 30cm apart, spacing seeds (or more accurately, seed clusters) every 10cm. Thin to the strongest seedling once germinated. Beetroot is relatively frost-tolerant and can be sown slightly earlier than tender crops. Harvest from July when roots are golf-ball to tennis-ball size for best flavour.
Shrubs and Perennials to Plant in Spring
14. Hydrangeas
May is an ideal time to plant hydrangeas — warm soil, adequate moisture, and the whole growing season ahead supports strong establishment. Position in morning sun with afternoon shade; scorching afternoon sun wilts even well-watered plants. Soil pH affects flower colour in mophead varieties: acid soil (below pH 6) produces blue flowers, while alkaline soil gives pink. Our hydrangeas guide covers all the main species and varieties suited to UK gardens.
15. Lavender
Plant lavender in May for best establishment. It demands full sun and sharply drained soil — add grit when planting in clay. Don’t feed lavender; nutrient-rich soil encourages vegetative growth at the expense of flowers and reduces the plant’s natural compact form. English lavender (Lavandula angustifolia) is the most hardy and longest-lived for UK gardens, while French and Spanish varieties need more protection in colder areas.
16. Roses
Bare-root roses are best planted in autumn to spring, but container-grown roses can go in any time the ground is workable. Spring planting in April or May gives roses the warm growing season to establish before their first winter. Prepare the planting hole generously and add mycorrhizal fungi to the roots to support establishment. Our roses care guide covers planting, feeding, pruning, and disease management in full.
17. Hardy Geraniums (Geranium spp.)
Hardy geraniums (cranesbills) are among the most versatile and low-maintenance perennials for spring planting. Plant divisions or pot-grown specimens in April/May in almost any position — sun or partial shade, most soil types. They spread to form weed-suppressing ground cover and flower reliably from May onwards. Cut back hard after the first flush of flowers to encourage a second bloom in late summer.
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→ View My Garden Calendar18. Hostas
Plant hostas in spring when they’re just emerging from dormancy — April is ideal. They prefer damp, humus-rich soil in shade or dappled light. Hostas are primarily grown for their dramatic foliage rather than flowers. Our hostas guide covers variety selection, slug protection (their main challenge), and division techniques. A single plant can be divided repeatedly to create large drifts over time.
Hardy vs Half-Hardy Plants: Timing the Difference
Understanding the distinction between hardy and half-hardy plants is the single most important concept in spring planting timing:
- Hardy annuals (cornflowers, sweet peas, nasturtiums) — tolerate frost; can be sown direct from March/April
- Half-hardy annuals (cosmos, marigolds) — frost will kill them; start indoors and plant out after last frost
- Tender perennials (dahlias, cannas) — no frost tolerance; start under cover and only plant out when all frost risk has passed
- Hardy perennials and shrubs (roses, hostas, geraniums) — fully frost-hardy once established; can be planted as soon as soil is workable
Starting from Seed vs Buying Plants
Both approaches have their place. Starting from seed is significantly cheaper — a packet of 50 seeds costs the same as a single pot plant — and gives access to a much wider range of varieties. However, it requires equipment (propagators, grow lights or a warm windowsill), time, and some experience.
Buying pot-grown or plug plants is faster, more reliable for beginners, and better for plants that are tricky to germinate or require a very long growing season (peppers, aubergines). For large plantings of easy annuals like sunflowers or nasturtiums, seed is almost always better value.
Planting by UK Hardiness Zones 7–9
The UK broadly spans zones 7–9:
- Zone 7 (upland Scotland, North Pennines): last frost typically late May; stick to the most cold-tolerant varieties; give tender plants extra time indoors
- Zone 8 (most of England and Scotland): last frost mid-to-late May; standard planting guidance applies
- Zone 9 (London, South West England, coastal Wales): last frost early-to-mid May; can push planting dates earlier; wider range of less-hardy plants succeed long-term
These are broad guides — local microclimates (sheltered south-facing walls, frost pockets in low-lying gardens) can shift your effective last frost date by several weeks in either direction.
Frequently Asked Questions
What can I plant in March in the UK?
In March you can plant hardy plants including sweet peas, onion sets, shallots, peas, broad beans, and hardy perennials. Start tomatoes, peppers, and half-hardy flowers indoors in a heated propagator. Avoid planting tender vegetables outdoors until after the last frost.
What vegetables can I plant in April?
April is good for planting potatoes, lettuce, beetroot, spinach, and carrots direct. You can also plant asparagus crowns, and sow courgettes, French beans, and runner beans indoors in pots for planting out in May. Brassicas (cabbage, broccoli) can be started under cover in April.
What can I plant in May after the last frost?
After the last frost in May, you can plant out tomatoes, courgettes, cucumbers, basil, French beans, runner beans, sweetcorn, dahlias, cannas, and all tender bedding plants including petunias, marigolds, cosmos, and begonias.
What flowers can I grow from seed in spring?
Excellent spring-sown flowers include sunflowers, nasturtiums, cornflowers, calendulas, cosmos, sweet peas, nigella (love-in-a-mist), and poppies. Hardy types can go direct from March; half-hardy types should be started indoors and planted out in May.
Is it too late to plant if I miss March and April?
No — May is still a productive planting month, especially for tender crops that couldn’t go in earlier. Many perennials and shrubs can be planted throughout the growing season from container. The main things you’ll miss are the very earliest harvests from cool-season crops, but most spring planting activities remain viable well into June.
Sources
- Royal Horticultural Society. What to plant in spring. RHS. https://www.rhs.org.uk/advice/seasonal-advice/spring-gardening-jobs
- Royal Horticultural Society. Hardy annual flowers. RHS. https://www.rhs.org.uk/plants/types/annuals/hardy-annuals-to-sow
