How to grow Achillea

What are achilleas?

Achilleas are hardy herbaceous perennials in the daisy family (Asteraceae), instantly recognisable from their flat or domed heads composed of many tiny, individual, daisy-like flowers. They generally produce a spreading mat of ferny foliage which often overwinters. A few are low-growing alpines, but most produce upright flower stems 30 to 180cm tall depending on species. They are found throughout the temperate northern hemisphere and two are widespread natives in UK and Ireland: sneezewort (Achillea ptarmica) and yarrow (A. millefolium). A rare third native

A native plant is one that originated or arrived naturally in a particular place without human involvement. In the British Isles, native plants are those that were here during the last ice age or have arrived unaided since.

, cottonweed (A. maritima), clings on in Co. Wexford. 

Choosing

When choosing which achillea to buy, consider the following:

Garden position:

• Most achilleas are mid-border plants, not too small and not too tall, but still ranging from 30-90cm, so check descriptions for their ultimate heights. Mid-sized plants are also good in containers; taller ones, such as 1.8m ‘Cloth of Gold’, can be used for prairie planting
• A few are low-growing so suitable for a rock garden or other sunny, well-drained spot where they will not be overcrowded
• Most achilleas revel in the sun, and need well-drained soil, but A. ptarmica and its varieties, such as double-flowered ‘The Pearl’, prefer moister soil and partial shade
• In wilder areas and species-rich lawns try yarrow (A. millefolium) or one of its coloured varieties
• If you want a large number of plants, consider seed-raised cultivars such as mixed ‘Summer Pastels’ or ‘Summer Berries’, dark red ‘Cassis’, deep yellow ‘Gold Plate’, or one of the species

Flower colour:

• There’s lots to choose between, from purest white to richest red, with shades to suit most colour schemes
• ‘Mondpagode’ is a good creamy white, ‘Moonshine’ a cool lemon and ‘Coronation Gold’ a rich golden-yellow. ‘Heidi’ is a bright purplish pink, ‘Lachsschönheit’ salmon pink and ‘Red Velvet’ a rich scarlet. These varieties are among the 17 achilleas that have an RHS Recommended: Award of Garden Merit, indicating they are reliable choices
• Another option is to choose a mixture such as rich ‘Summer Fruits’ or paler ‘Summer Pastels’, both of which can be grown from seed

Further inspiration

If you want to explore further, there are National Collections in Lincolnshire and Sussex. Or try our Find a Plant tool with images and descriptions and a range of filters to help narrow down your selection. 

Buying

Achilleas are widely available from late spring to early autumn as container-grown plants in 1-3 litre pots from garden centres and online. Smaller plants, in 9cm pots, may be available in early spring – these benefit from potting on

Moving a plant from one pot into a slightly larger one, once its roots have filled the current pot. Most container plants need potting on every few years. If you leave a plant in the same pot for too long, its roots will become overcrowded (pot bound), hindering growth.

into slightly larger pots then planting out in early summer after they have put on a little more growth. 

A few mail-order nurseries also sell bare-root

These have been lifted from the ground while dormant, with little or no soil around their roots. Various plants may be available bare root, including fruit trees, hedging plants and some perennials. They are generally cheaper than plants in containers, but are only available in winter/early spring, while dormant

plants from autumn through to early spring. These are often less expensive and avoid the use of new plastic pots but will need planting, or potting up, as soon as they arrive. 

Use the RHS Find a Plant tool to track down stockists of specific cultivars.

How to choose healthy plants

Buying: garden centre plants

Buying: mail order plants

When to plant

The ideal time to plant is in spring, when the soil has warmed up. However, they can be planted in autumn or winter provided the soil is not waterlogged

Describes soil or potting compost that is saturated with water. The water displaces air from the spaces between soil particles and plant roots can literally drown, unless they are adapted to growing in waterlogged conditions. Waterlogging is common on poorly drained soil or when heavy soil is compacted.

or frozen, or in summer as long as there is water available to ensure they don’t dry out.

Where to plant

Achilleas are generally tough and tolerant plants, but free-draining soil is a non-negotiable requirement for most and they will fail to thrive in cold, heavy clays or waterlogged soil. Full sun is their preferred situation, and they are drought tolerant once established, coping well with dry or impoverished soil. One exception is Achillea ptarmica and its varieties, which prefer moist soil and semi-shade. 

Most achilleas would suit a mixed border combined with other drought-tolerant plants like euphorbia, echinops, verbena and ornamental grasses. Their long flowering period, low maintenance needs and winter-interest seedheads also make them suitable for prairie planting.

Soil types

Perennial borders: choosing plants

Drought-resistant gardening

Prairie planting: creation and maintenance

Yarrow (A. millefolium), native

A native plant is one that originated or arrived naturally in a particular place without human involvement. In the British Isles, native plants are those that were here during the last ice age or have arrived unaided since.

to GB and Ireland, is ideal for growing in a sunny situation in the wild garden, rock garden or flower-rich lawn where it can support over 100 species of insect. However, it does spread readily and may be unwelcome in fine lawns or borders.

Yarrow in lawns

How to plant

There is no need to improve the soil before planting; nutrient-rich conditions will cause the plants to become tall and floppy. Dig a hole slightly bigger than the rootball

The roots and accompanying soil when a plant is removed from a container or lifted from the ground.

, settle the plant in at the same level it was in the pot, refill and firm the soil then water well.

Perennials: planting

Watering

Although achilleas are drought-tolerant once established, young plants will need watering in dry spells for the first year, while their roots become established.

Mulching

Mulching is not necessary for achilleas but if plants are growing in a border then they can be mulched alongside their neighbours. A low-nutrient mulch

Mulch is a layer of material, at least 5cm (2in) thick, applied to the soil surface in late autumn to late winter (Nov-Feb). It is used to provide frost protection, improve plant growth by adding nutrients or increasing organic matter content, reducing water loss from the soil, for decorative purposes and suppressing weeds. Examples include well-rotted garden compost and manure, chipped bark, gravel, grit and slate chippings.

, like leaf mould, will help suppress weeds and improve the soil’s structure without making the growing environment too rich. 

Mulches and mulching

Feeding

Plants in the ground do not need any additional feeding. 

Overwintering

Flowering stems will die at the end of the season but will often remain standing and are worth leaving for their structural interest and wildlife value – just tidy up any remains in spring. The basal leaf rosette may remain green but needs no winter protection.

Caring for older plants

Most achilleas benefit from being divided every three to five years to keep them healthy, vigorous and flowering well. Simply dig up your clump in spring and split it into smaller clumps, discarding any very woody or dead-looking sections, then replant. 

Growing in containers

Achilleas are well-suited to container growing with their sturdy stems, long flowering season and wide colour range. Varieties of Achillea millefolium, and hybrids that are not too tall, would all be good choices. Containers are also a good way to grow smaller achilleas that need very sharp drainage, and benefit from being moved to a sheltered spot in winter, such as beside a wall, or in an unheated greenhouse or coldframe, to avoid pots getting too wet. Plant into multi-purpose peat-free compost

Can refer to either home-made garden compost or seed/potting compost: Garden compost is a soil improver made from decomposed plant waste, usually in a compost bin or heap. It is added to soil to improve its fertility, structure and water-holding capacity. Seed or potting composts are used for growing seedlings or plants in containers - a wide range of commercially produced peat-free composts are available, made from a mix of various ingredients, such as loam, composted bark, coir and sand, although you can mix your own.

mixed with horticultural grit at a ratio of three parts compost to one part grit.

Plants in containers will need regular watering – check daily during hot, dry spells as the compost will dry out faster. They will need less water in winter but should still be checked occasionally. Newly planted containers will run out of nutrients

To grow well, plants need a wide range of nutrients in various amounts, depending on the individual plant and its stage of growth. The three key nutrients usually taken up from the soil are nitrogen, phosphorus and potassium. Plants also need carbon, oxygen and hydrogen to make carbohydrates — their main energy source. Carbon and oxygen come from the air as carbon dioxide, while hydrogen is drawn from water absorbed by the roots. Other important soil nutrients include magnesium, calcium and sulphur. Most garden soils contain enough of these nutrients to support healthy plant growth.

in the compost after a month or two, so plants will need additional feeding. Either mix some slow-release general-purpose fertiliser granules into the compost at planting time, and repeat each spring, or use a multi-purpose liquid fertiliser, such as seaweed feed, at half strength every 10 days or so while the plants are growing actively. 

How to plant up a container

Container maintenance

Regular deadheading

Deadheading is the process of removing spent flowers from plants to encourage more blooms and prevent seed production. This helps to redirect the plant's energy into producing more flowers rather than producing seeds.

should encourage plants to flower into autumn. Achillea is also a candidate for the ‘ Chelsea chop

The Chelsea chop is a pruning technique to bring floppy plants under control and extend their flowering season. Named after the RHS Chelsea Flower Show in late May because the task's timing coincides. Cut back the flower stems by up to a half (the taller the variety the more you can cut it back) for new compact growth and later flowers. 

’, to delay the start of flowering and encourage the development of shorter, sturdier stems.

Chelsea chop

Border achilleas are good for cutting for fresh or dried arrangements and come in a wide range of colours.

Cut flowers: cutting and conditioning

Achillea seedheads stand firm over winter, so can be left to provide food and shelter for wildlife before being cut down to ground level in early spring. Remove any untidy remaining foliage at the same time.

Achilleas are easily propagated by division in spring, or by taking cuttings

A method of growing new plants from parts of an existing plant, such as sections of root, stem, leaf or bud. When prepared correctly and planted in the right conditions, they can produce roots and eventually become independent plants. There is a wide range of different methods for taking cuttings, depending on the plant and time of year.

from young spring growth, known as basal cuttings

These are cuttings taken from strong new shoots sprouting from around the base of a plant, often in spring.

. You can also grow them from seed – sow in spring onto moist peat-free seed compost

Seed compost is a free-draining compost formulated for germinating seed. It often contains a mix of fine materials including sterilised loam, coir, coarse sand or grit. It contains low levels of nutrients, as high levels could damage seedlings.

. Germination

Germination is the process by which a seed develops into a new plant. It starts with the seed coat absorbing water, expanding and splitting, which allows oxygen and water into the seed so its food reserves can be broken down and used by the embryo for growth. The first root (called the radicle) pushes into the soil to anchor the new plant in place and start absorbing water and nutrients. The first shoot (called the plumule) then grows upwards, out of the soil, towards the light.

takes 5-10 days. Once seedlings

A seedling is a young plant grown from seed.

have their true leaves, transplant carefully to modules

Small individual cells, usually in a tray, used for sowing seeds. The resulting seedlings can be transplanted with minimal root disturbance.

or 9cm pots and grow on. Plants should flower in their first year.

Perennials: dividing

Cuttings: softwood

Achilleas should live for many years, with regular division, provided the growing conditions are suitable. Plants may dwindle in soils which are too wet, and they will suffer in very cold, wet winters.

Achilleas may be affected by powdery mildew

A white powdery fungal growth on the surface of leaves, buds, petals and shoots of roses and many other plants. The foliage may become discoloured, heavily infected young leaves may be curled and distorted, and the plant’s vigour may be reduced.

if conditions are too dry or root rot in wet conditions. They can also be susceptible to aphids. 

Powdery mildews

Aphids

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