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What are Chrysanthemums? | How to grow Chrysanthemums | Where to Plant | When to Plant | How to Plant | How to Care for Chrysanthemums | How to Grow from Seed | Common Issues | Inspiration
What are Chrysanthemums?
Chrysanthemums are perennial plants, which means that they die down over winter and reappear the following year. They can be hardy or half-hardy. Chrysanthemums (more usually called ‘mums’) are invaluable late bloomers and are easy to grow as long as you can provide full sun or partial shade, rich soil, and good drainage. If the area gets several hours of direct sunlight every day, that’s ideal.
There are hundreds of varieties available in a bewildering range of shapes, colours and sizes that provide stunning blooms long after summer and into autumn.
How to Grow Chrysanthemums
If you’re searching for striking summer and autumn colour, you can’t do better than chrysanthemums. Offering flowers from August to October, mums come in an incredible range of striking shades. As a rule, planting perennial chrysanthemums is best done in the spring to early summer because this gives the flower a chance to put down strong roots and help them survive over winter.
Where to Plant Chrysanthemums
Chrysanthemums are sun-lovers and prefer well-drained moist soil. Early flowering chrysanthemums are usually planted in borders and will flower from late summer to autumn. Late-flowering chrysanthemums flower in winter and are normally grown as houseplants.
When to Plant Chrysanthemums
When to plant chrysanthemums will depend on where you live. If you live in the South, you can plant them out from late May. Northern areas might have to wait until June to avoid late frosts.
How to Plant Chrysanthemums
Outdoors, dig a hole slightly wider and deeper than the pot your plant is currently in. Add a handful of organic matter, such as compost or well-rotted manure in the bottom of the planting hole and pack the soil back firmly around the plant before watering well. When planting chrysanthemums, space them apart to allow good air circulation. Decent spacing also helps them to resist diseases such as powdery mildew.
Growing Chrysanthemums in containers
Alternatively, you can grow your chrysanthemums in pots indoors from early spring, moving them outside once the weather warms up in late spring or early summer. Choose a pot that suits the size of the plant and follow these easy steps:
1. Fill a container with drainage holes with peat-free, multi-purpose compost.
2. Plant your chrysanthemum, firm it in well and give it a good drink.
3. Provide support by inserting a stake or bamboo cane at the side of the plant and tying them in as they grow so they don’t keel over if it’s windy.
How to Care for Chrysanthemums
- Make sure they are planted in a sunny spot in the garden.
- Water freely throughout the summer.
- Chrysanthemums require fertiliser during the growing season to perform to their best.
- Pinch out or deadhead if required.
- If you have moved your pots outside, be sure to bring them back indoors or move to a sheltered place if gales, hail or cold spells are forecast.
Removing chrysanthemum flower buds (disbudding)
To produce larger flowers, flower stems must be disbudded. This consists of nipping out all buds and side shoots, just leaving a top bud. You can remove side shoots when they are about 2 cm long. If you want to produce a spray of flowers, simply do the opposite: remove the top bud and leave all the side buds.
Watering
Chrysanthemums are thirsty plants. If they’re deprived of water they will wilt, refuse to flower, or die back, so be sure to water them regularly (especially throughout dry periods).
Feeding
Chrysanthemums are greedy, heavy feeders. For the best flower displays, feed your plants every two weeks from midsummer with a high nitrogen fertiliser when the plants are in leafy growth, then switch to high potash fertiliser (any tomato feed will do,) as soon as flower buds are seen.
Mulching
Mulching newly planted chrysanthemums with a 2.5 cm ring of organic material after planting will help boost flowering, feed the plant and help trap moisture in the soil.
Deadheading
Deadhead spent flowers by hand, with scissors, secateurs or with garden shears.
How to propagate chrysanthemums
Like many garden perennials, hardy chrysanthemums can become overcrowded and benefit from being divided every few years. This is the fastest and easiest way to get new plants and is best done in late spring.
Propagating chrysanthemums by division: In spring, dig up a clump and divide it into several pieces with a sharp spade. Replant pieces into the final planting positions, cover them with garden soil, and water well.
Propagating chrysanthemums by cuttings: Taking cuttings is another reliable way to propagate chrysanthemums. Cuttings can be taken in April from plants already in growth. If you have a greenhouse or cold frame, you can buy rooted cuttings in early spring and pot them straight away in March and February.
Propagating chrysanthemums by seed: The trouble with growing chrysanthemums by seed is they don’t always reliably mirror the features of the parent plant so it’s potluck what turns up. That said, a few cultivars can be grown reliably from packet seed.
How to Grow Chrysanthemums from Seed
Sow Chrysanthemum seeds under cover from February to April or directly in the garden in April. To get started, you’ll need a clean seed tray or pot and fresh potting compost:
1. Fill your seed tray or pot with compost, firm it down and water it, allowing it to drain before sowing seed.
2. Sow the chrysanthemum seeds on the surface of the soil, covering the seed with a light sprinkling of soil.
3. Water the seeds lightly again and then place the pot or container in a warm, sunny location or heated propagator. Keep the soil moist, but not wet and keep an eye on the seeds until they germinate which usually takes about two weeks.
4. When the leaves are large enough to handle, prick out seedlings into individual pots or modules and grow on until large enough to plant in the garden, normally around May and they will flower the same year. Always handle seedlings by the leaves because even baby plants can grow new leaves, but they can’t grow new stems.
5. Alternatively, you can sow them directly in the ground in a well-prepared bed that has been raked to remove stones and lumpy soil. Cover them lightly with mulch and keep the bed moist.
Growing Chrysanthemums: Problem-solving
Growing chrysanthemums is enjoyable but like all garden plants, they can be attacked by pests or diseases. The main suspects to watch out for are aphids, earwigs, slugs and snails. See our guide for easy ways to spot problems and how to deal with them.
Aphids:
Sap-sucking bugs that are easy to spot and are usually, green, black or grey. You’ll find them in clusters along leaves and stems and the moment you spot them, take action as they can weaken the plant.
Symptoms: Look for clusters along leaves and stems or a sticky substance known as honeydew which they excrete as they feed.
Treatment: Affected leaves or shoots should be removed and destroyed although a weekly blast with the hose pipe and soapy water is usually enough to dislodge them. Insecticides are available but natural methods are kinder to your garden and wildlife.
Slugs and snails:
Love nibbling on young foliage and leave plants with ugly, chewed leaves that can impair the plant’s ability to produce energy.
Symptoms: Leaves are nibbled around the edges or large chunks of foliage are eaten.
Treatment: Pick off slugs and snails by hand or use slug pubs or pellets at the base of the plant.
Earwigs:
Earwigs love chrysanthemums as much as we do, eating both leaves and flowers and hiding around the base of the plant.
Symptoms: Ragged holes at the edges and in the centre of leaves.
Treatment: Make homemade earwig traps using an upturned flowerpot filled with dried grass or straw and leave it at the base of the plant and also upside down on the top of bamboo canes to encourage earwigs to hide in them instead and empty daily.
Powdery Mildew:
A fungal disease that affects plants if they are crowded too closely together resulting in poor air circulation. It is triggered by high temperatures, or prolonged dry or humid spells both in the greenhouse and outdoors, drying out plant roots.
Symptoms: A grey dusty powder over the leaves.
Treatment: Remove affected leaves and dispose of them or spray them with an eco-friendly fungicide.
White Rust:
It's a fungal disease that can affect chrysanthemums and the effects can be severe.
Symptoms: Watch out for pale yellow spotting on leaf surfaces followed by pinky-white pustules on the undersides.
Treatment: Remove all affected leaves and burn them straight away to avoid them becoming airborne. In the greenhouse try to keep humidity down by ensuring good ventilation by leaving vents open. Avoid taking cuttings from affected plants.
Chrysanthemums We Recommend
There are so many fabulous chrysanthemums around and once you discover them, we can promise it will be the start of a lifelong love affair. Here are some of our favourites: