You can propagate mums two easy ways in spring: take short cuttings from the new shoots, or dig up and divide an established clump once growth has started. Cuttings give you many new plants from one parent, while division gives you fewer but larger plants that bloom the same fall.
Picking a method for your mums by season
Garden mums, or chrysanthemums, are sturdy perennials that spread quickly, and they propagate readily. Spring is the time for both main methods, because that’s when the plant is pushing fresh shoots.
| Method | When | What you get | Best for |
|---|---|---|---|
| Basal cuttings | Spring, from vigorous new shoots | Many small plants | Multiplying a favorite color cheaply |
| Division | Spring, once growth has started | A few larger plants | Renewing an old clump with a dead center |
| Seed | Spring sowing indoors | Variable plants | Experimenting rather than copying a plant |
Cuttings and divisions are clones, so they match the parent’s flower color and form. Seed from a hybrid mum may not, which is why most gardeners stick with the first two.
Taking mum cuttings from spring shoots
The Royal Horticultural Society’s method uses basal softwood cuttings, the young shoots coming up from the base of the plant.
- Choose vigorous new shoots from the outside of the clump.
- Cut them 2 to 3 inches long.
- Strip off the lower leaves so no foliage sits below the soil.
- Insert each cutting into a pot filled with a mix of half multipurpose potting mix and half horticultural grit, or a similar gritty mix.
- Keep the pots at 50 degrees Fahrenheit or warmer in bright, indirect light, ideally under a clear cover to hold humidity.
- Expect roots in about three weeks. If a cutting resists a gentle tug, the mum has formed roots.
- Move the young plants into larger pots as they grow, and plant them out after a couple of months.
Take a few more cuttings than you need. Some always fail, and extras make good gifts.
Dividing a crowded mum clump
Older mums lose vigor and often die out in the middle while the outer edge keeps growing. Clemson Cooperative Extension recommends dividing garden mums every year or two, and NC State Extension suggests dividing in spring every few years to keep plants from getting congested.
Wait until new shoots appear, then dig up the whole clump. Discard the woody, tired center. Pull or cut the healthy outer sections apart so each piece has several shoots and its own roots. Replant them at the same depth they grew before, spaced so air can move between plants, and water them in well.
A sharp spade or an old bread knife cuts through a tight root mass more cleanly than tearing it by hand. Pot up any spare divisions, keep them watered in light shade for a week or so while they settle, then plant them out or share them with neighbors.
Pinching young mums for a fuller fall show
New mums, whether from cuttings or divisions, grow tall and floppy if left alone. Pinching removes the growing tip so the plant branches, and every branch carries flowers. Clemson Extension advises removing the top half inch to an inch of new growth about every four weeks, starting when the plant is 6 inches tall.
Stop pinching in summer so flower buds can form. Clemson’s cutoff in South Carolina is early July in the upper Piedmont and mountains and early August at the coast, and NC State places the last cut around mid August. Your local extension office can give the right pinching cutoff for your area, and colder regions usually stop sooner.
Giving the new mum plants a good spot
NC State lists Chrysanthemum x morifolium as hardy in USDA zones 5a through 9b and calls for full sun, meaning direct sunlight for six or more hours each day. Too much shade makes mums sprawl instead of growing upright. Plant young mums in well drained soil, water them regularly while they establish, and keep a note of which cuttings came from which parent so you can repeat the colors you liked next spring.
Frequently asked questions
Can you root mum cuttings in water?
Some gardeners try it, but the method the Royal Horticultural Society describes roots mum cuttings in a gritty potting mix kept at 50 degrees Fahrenheit or warmer, with roots in about three weeks. Starting in soil means the young plant never has to adjust from water to a pot.
Can I propagate mums in the fall?
Fall is when mums bloom, and flowering stems make poor cuttings. Division and cuttings both work best in spring, when the plant sends up fresh shoots. If you buy a potted mum in fall, plant it or keep it through winter and propagate from its new growth the following spring.
How often should I divide mums?
Clemson Cooperative Extension suggests dividing garden mums every year or two, while NC State Extension says every few years in spring. A clump with a bare or dead center and weaker flowering is a clear sign it's time. Divide once new shoots appear so each piece has growth and roots.
