Donkey's tail is the sedum that gets people talking. Long, rope-like stems spill from a hanging pot, each one packed with fat, frosted blue-green leaves that overlap like plaited hair. A mature plant can trail almost a metre, and it looks as good in a kitchen window as in a conservatory.
It is also very different from the hardy stonecrops in your rockery. This Mexican species will not survive a British winter outdoors, and its leaves fall off at the slightest knock. Here you will learn where to grow it, how to water it, how to handle it without leaving a trail of leaves, and how to turn those fallen leaves into new plants.
Sedum morganianum, donkey's tail at a glance
- Botanical name Sedum morganianum
- Common name Donkey's tail, burro's tail, lamb's tail
- Plant type Tender, trailing evergreen succulent grown as a houseplant in the UK
- Hardiness RHS H1c (needs a minimum of around 5 to 10C, not frost hardy)
- Height and spread Stems trail 30 to 60cm, and can exceed 90cm on old plants, with a spread of about 30cm
- Flowering Occasional clusters of small pink to red flowers at the stem tips in summer, rare indoors
- Foliage Plump, tear-shaped, blue-green leaves about 2cm long, dusted with a pale waxy bloom
- Position Bright light with some direct sun indoors, a sheltered sunny spot outside in summer only
- Soil Very free-draining cactus and succulent compost with added grit
- Good for Hanging pots, high shelves, sunny windowsills and conservatories
Not like the sedums in your garden
Most sedums sold in the UK are tough little plants rated H7 that sit happily on roofs through hard frost. Sedum morganianum is rated H1c by the RHS, which means it needs glasshouse or indoor warmth and should never drop much below 5C. Treat it as a houseplant first and a summer patio visitor second.
Watering and feeding differ too. A pot of donkey's tail indoors needs regular attention through spring and summer, whereas a hardy sedum in the ground can be left to rainfall. If you are looking after outdoor types as well, our general sedum care guide covers those.
Finding the brightest spot indoors
Good light keeps the stems tight and the leaves packed closely together. A south or west-facing window, or a conservatory, suits it well. In a dim room the stems stretch towards the glass, gaps open up between the leaves and the colour fades to a pale green.
Very strong sun magnified through glass in midsummer can bleach or scorch the leaves, especially on a plant that has just moved from a darker spot. Turn the pot a quarter every couple of weeks so all sides get their share and the tails grow evenly.
Handle with care
Those plump leaves are attached by a tiny point, and brushing past, watering clumsily or moving the pot will knock them off. Choose a permanent home before the stems get long, ideally a hanging basket or high shelf where nobody walks into it.
When you do need to move it, lift from underneath the pot and carry it with the stems resting over your forearm. Do not worry too much about the odd dropped leaf, as it is part of owning this plant and each one can grow into a new plant.
Watering through the seasons
From April to September, water thoroughly whenever the compost has dried out completely, which is often every 10 to 14 days indoors. Let any excess drain away and never leave the pot sitting in water.
From October to March, growth slows and the plant needs far less, perhaps once a month in a cool room. Your plant will tell you what it needs. Slightly wrinkled, soft leaves mean it is thirsty, while yellow, translucent or mushy leaves and blackening stems mean too much water.
- Water the compost directly with a narrow spout, not over the trailing stems.
- Use a pot with drainage holes, as decorative pots without them invite rot.
- Water a little more in a warm, sunny room and less in a cool one.
Compost, feeding and repotting
Grow it in a cactus and succulent compost with an extra handful of grit or perlite. A terracotta pot helps the roots dry out between waterings.
Feed once a month from April to August with a half-strength cactus or general liquid fertiliser, and stop over winter. Repot only when the plant is clearly crowded, every two or three years in spring. It will lose leaves in the process, so have a tray of gritty compost ready to catch and root them.
Summer outdoors, winter inside
Once nights stay above about 10C, usually from June, donkey's tail can spend the summer outdoors. Pick a sheltered, sunny spot under the eaves, out of strong wind that snaps the stems and heavy rain that waterlogs the pot. Acclimatise it over a week in light shade first.
Bring it back inside in September, before the nights turn cold. Over winter it is happiest in a bright room around 10 to 15C, and it will tolerate a little cooler if kept dry, but frost kills it outright.
Growing new plants from fallen leaves
Collect healthy dropped leaves, leave them on a dry plate for a few days so the broken end seals, then lay them flat on a tray of gritty compost. Mist lightly every few days. Tiny roots and a pink-green rosette appear within a few weeks, and the old leaf gradually shrivels away.
Stem cuttings give faster results. Snip off a 10cm tail, strip the bottom few centimetres of leaves, let it dry for a couple of days and push it into a small pot of compost. Plant several cuttings around the rim of one pot to fill it quickly.
Mealybugs, rot and pet safety
Mealybugs are the most common pest indoors. Look for white, cottony tufts tucked between the leaves and remove them with a cotton bud dipped in surgical spirit. Leggy, gappy stems mean too little light, and stems that rot at the base mean overwatering, so take healthy tip cuttings and start again.
Donkey's tail is listed as non-toxic to cats and dogs by the ASPCA, which makes it a sensible choice for homes with pets. The trailing stems can still tempt a playful cat, so a high hook keeps both plant and leaves intact.
Questions about Sedum morganianum, donkey's tail
Why is my donkey's tail dropping leaves?
The leaves are very loosely attached, so knocks and handling are the usual cause. Leaves that drop and look shrivelled point to underwatering, while soft yellow ones suggest overwatering. Keep the plant somewhere it will not be disturbed and adjust your watering.
Can donkey's tail live outside in the UK?
Only in summer. It is rated H1c and cannot cope with frost, so it should come back indoors by September. Outside, give it shelter from wind and heavy rain.
What is the difference between donkey's tail and burrito sedum?
Burrito, sold as Sedum burrito or Sedum morganianum 'Burrito', has shorter, rounder leaves that sit tightly along the stem. Classic donkey's tail has longer, pointed leaves and makes longer tails. Care is almost identical, and both are tender.
How fast does donkey's tail grow?
It is a slow grower, adding perhaps 15 to 30cm of stem in a good year with plenty of light. Growth largely stops over winter. Planting several cuttings in one pot makes a fuller display more quickly.
With bright light, a careful hand on the watering can and a spot where nobody brushes past, donkey's tail will keep lengthening for years. Explore it alongside our hardy outdoor stonecrops in the sedum collection.