Light
As with many succulents, donkey’s tail thrives best with lots of warm sunlight, though it will tolerate a partial shade location. If you’re choosing to house your plant indoors, opt for a sunny windowsill that boasts several hours of daily light. If you’re growing your succulent outdoors, place it in a pot or spot in your garden that gets plenty of morning sunlight but is partially shaded during the more aggressive afternoon hours to avoid scorching its leaves.
Soil
In order for your donkey’s tail succulent to grow successfully, it should be housed in well-draining, sandy soil. If you plan to plant your succulent in a container (either to keep outdoors or to live inside), opt for a gritty soil mixture suited specifically for cacti or succulents. Choose a container with a drainage hole to ensure the roots don’t sit in water. If you’re including it as part of a larger garden, be sure to choose a spot amongst other plants that prefer well-drained soil, as too much retained water will cause it to die (you can even consider mixing sand into your ground soil to aid in drainage). Additionally, donkey’s tail thrives in soil with a neutral to alkaline pH but isn’t too picky in this regard.
Water
When it comes to watering your donkey’s tail succulent, less is more. Like many succulents, donkey’s tail is drought resistant once established, so you’ll want to water it more frequently during its spring and summer growing season, then taper off throughout the fall and winter months. Generally, opt for a single heavy watering each month if your plant is indoors, increasing to once every two or three weeks if you’re housing your succulent outdoors. A good rule of thumb: The soil of your succulent should dry out completely in-between waterings. Check the soil with your finger to make sure the soil is dry at least an inch down before watering the plant. To aid in drainage, choose a pot with holes at its base; a terracotta or clay material can also help wick water from the soil. When in doubt, err on the side of less watering rather than more—donkey’s tail holds moisture in its plump leaves and can tolerate periods of drought but is not at all tolerant of over-watering. The leaves will also begin to pucker like a raisin, indicating that it’s time to water.
Temperature and Humidity
Donkey’s tail prefers warm weather, though it stands up better to cooler temperatures than some other succulents. On average, try to maintain an environment of 65 degrees to 75 degrees Fahrenheit whether you keep your plant indoors or outdoors. It can survive when exposed to temperatures as low as 40 degrees Fahrenheit, but only briefly, so be sure to bring it inside before the first frost or move it away from drafty windows in the winter months. When it comes to humidity, donkey’s tail has no special needs. In fact, it prefers average levels of humidity and can rot if attempts are made to increase the humidity of its environment (so no need to mist its leaves or keep it somewhere more humid, like a bathroom).
Fertilizer
While fertilizing donkey’s tail succulent isn’t totally necessary to its successful growth, it also won’t hurt and can be a great way to give the plant added nutrients. Focus on feeding your plant at the beginning of its growth season in spring, using a controlled release, balanced 20-20-20 fertilizer, which contains equal parts nitrogen, phosphorus, and potassium. Mature succulents may prefer the fertilizer at one-quarter strength, while younger plants may prefer fertilizer with less nitrogen.
Types of Donkey’s Tail
There are two closely related forms of this plant.
Sedum morganianum, the species form, is usually known as “donkey’s tail”, and it can be identified by its notably pointed leaves. S. morganianum ‘Burrito’ is the only named cultivar sold, usually marketed as “burro’s tail.” It is identified by its more rounded leaves. Other than this, the plants are identical.
Pruning
Should stems grow sparse from leaves that drop off, you can clip off the stem near the plant crown. Otherwise, no pruning is necessary—unless to harvest leaves for propagating new plants. Removing leaves from a portion of the stem can sometimes stimulate side-branching at this point.
Propagating Donkey’s Tail
Since donkey’s tail rarely flowers indoors, propagating by seed isn’t a viable option. But, like most succulents, donkey’s tail is easy to propagate through its leaves, which is good news, as they seem to fall off at the slightest touch.
Potting and Repotting Donkey’s Tail
Because of their fragile nature, great care should be taken when repotting a donkey’s tail succulent. Wait until it’s absolutely necessary. The plant doesn’t mind being a bit root bound, so you’ll only need to repot once every few years. Be careful to avoid losing many of your “tails” and leaves to jostling when replanting. However, if you must repot your succulent, you will find the most success in the warmer months. Make sure the soil is completely dry before beginning, then gently remove the succulent from its current vessel, knocking away any old soil from the roots of the plant. Place it in a new pot (a shallow clay pot works best) and backfill with soil, making sure to spread out the roots in the new, larger pot. Allow it to “rest” for a week or so before giving it the first watering in its new home.
Overwintering
Whether you are growing donkey’s tail indoors as a houseplant or outdoors in a climate where it is hardy, reduce watering to every other month in the winter and omit feeding during this period of low growth.
Common Pests & Plant Diseases
The donkey’s tail succulent is not particularly susceptible to pests, but if it does experience an infestation, it’s likely to be from aphids. Though aphids can typically be hosed off a plant, that’s not the best solution for donkey’s tail succulents given their fragile nature. Instead, opt to mist them every few days with diluted organic neem oil until the aphids disappear (typically around two to three weeks). Mealybugs can also be an issue and can also be handled with neem oil. When planted outdoors, slugs and snails can be a problem, best handled by picking them off by hand or setting out baits for them. The only significant disease problem is root rot, which can occur if the plant is overwatered or grown in dense, poorly draining soil.
How to Get Donkey’s Tail to Bloom
This plant blooms infrequently, especially when grown indoors, and they are not likely to bloom at all until they are quite mature. The small, yellow, white, or red flowers, when they do appear, bloom in late spring or early summer. The flowers are not especially showy, but growers have noticed that slightly stressing the plant with cooler outdoor temperatures (though not to such excess that it endangers the plant) sometimes stimulates them to bloom. These plants also need plenty of sunlight to bloom, but feeding should be kept at a minimum.
Common Problems With Donkey’s Tail
Donkey’s tail is a largely problem free plant that thrives on neglect, but there are several cultural issues that may raise questions:
Leaves Turn Gray
If you notice your plant turning grey or a very dull green (rather than its typical rich blue-green), that’s probably a sign that it’s getting too much harsh light. You may also notice a chalky white, waxy appearance on the beaded leaves of your donkey’s tail succulent. Don’t stress—it’s a completely normal occurrence called epicuticular wax, which the plant produces to protect itself from too much harsh sun exposure.
Leaves Shrivel and Shrink
When the leaves of donkey’s tail curl up and shrink, it is usually because the plant needs water. This is not such a big problem, as they will soon swell up again as soon as you give it a thorough watering. Many growers find that it’s better to wait for for this sign before watering than to water too frequently.
Stems Turn Soft and Collapse
If the stems on your donkey’s tail collapse and turn soft, it’s likely because the plant has been overwatered and rot is setting in. If you immediately allow the plant to dry out, it sometimes can be saved, but with advanced cases of rot, you’ll need to discard the plant.
Leaves Wilt, Fall Off
If you notice leaves drooping and beginning to fall off, don’t mistake this as a sign the plant needs water—with donkey’s tail, this is actually a sign that the plant is overwatered.
