Moss rose plants (Portulaca grandiflora) are popular flowering annuals sold in the spring. If you see leftover moss rose plants on clearance sale in the summer, you might notice the plants are usually just as lovely as they were in the spring, which is a testament to the plant's toughness. The medium green, cylindrical, succulent leaves of moss rose are another clue to the plant's hardiness—namely its tolerance to drought conditions.
Native to South America, these plants grow to be between 3 and 9 inches tall and spread to create a dense mat, making moss rose a good option for a ground cover. The flowers come in several bright colors and often have ruffled petals, looking very similar to miniature roses. The blooms grow in clusters on reddish stems and typically don't open on cloudy days or at night. Moss rose is easy and quick to grow and is best planted in the spring after the danger of frost has passed. Gardeners should carefully consider where they plant moss rose in their landscape, as all parts of the plant are toxic to dogs and cats.
|Common Name||Moss rose, moss rose purslane, Mexican rose, sun rose, rock rose|
|Botanical Name||Portulaca grandiflora|
|Plant Type||Annual flowering succulent|
|Mature Size||3–9 in. tall, 6–12 in. wide|
|Soil Type||Sandy, well-drained|
|Soil pH||Neutral to Acidic|
|Bloom Time||Early summer to frost|
|Flower Color||White, orange, yellow, red, pink|
|Hardiness Zones||2–11, USA|
|Native Area||South America|
|Toxicity||Toxic to dogs, toxic to cats|
Moss Rose Care
Moss rose plants are a popular choice for growing in container gardens, along the front edge of garden bed borders, as edging along paved walkways, on top of stone walls, and in rock gardens. In addition, the trailing habit of moss rose works well in hanging baskets. Moreover, moss rose doesn't typically spread outside of its bounds as a ground cover, so it's ideal for small gardens.
These plants will flourish in poor, dry soils where many other plants might struggle—in fact, soil that's too wet can actually kill them. Moss roses typically bloom from summer to the first frost of the fall without any deadheading required. As annuals, the plants will die at the end of the growing season, but they do produce seeds that can potentially germinate and sprout the following year.
Moss roses are not affected by any notable pest or disease problems, though aphids might occasionally bother the plants, especially in the spring. With aphids, you might notice a sticky substance on the leaves, as well as yellowing and wilting of the foliage. Spray affected plants with insecticidal soap to treat the problem.
Moss rose plants need six to eight hours of full sunlight on most days to look and bloom their best. If you try to grow them in a shady area, they will fail to produce flowers and the flowers they do have likely won't open.
These plants thrive in sandy and rocky soil and demand excellent drainage. If your garden bed has clay soil, grow your moss rose in containers rather than try to improve the clay soil drainage. Soil that retains too much water can easily cause the plant to die.
Moss rose plants have low moisture needs, though they aren't quite as drought-tolerant as cacti. The plants will tolerate periods of dryness, but flowering is usually better with some (well-drained) soil moisture. Plan to water the plant if you have a long stretch without rainfall—as a general rule of thumb, one deep watering per week during the hot summer weather should suffice.
Temperature and Humidity
A native of Brazil, Uruguay, and Argentina, moss roses like high heat and low humidity. It will tolerate cool, moist spring weather as long as it is frost-free. However, the best growth (and blooming) won't occur until the summer heat comes along. Moss roses are frost tender and will die back come winter, likely at the first deep freeze (if not earlier).
Moss roses can tolerate lean soil, so they typically don't need fertilizer. However, feeding the plant with a balanced, slow-release fertilizer at the time of planting can help promote healthy growth and profuse flowering. You can also fertilize twice during the plant's growing season, this time using a blend that's high in phosphorous for more bountiful blooms.
Types of Moss Rose
There are several different types of moss rose plants that are popular for landscape gardens. They include:
- 'Afternoon Delight': A moss rose varietal with 2-inch wide blooms that are open all day until the evening (longer than most other varietals).
- 'Duet' series: This varietal boasts bicolor flowers in yellow and red or yellow and pink.
- 'Fairy Tale' series: These varietals (with names such as 'Snow White' and 'Sleeping Beauty') resemble bomb-type peonies, with flowers that have a pom-pom center with flat petals that flare around the edges.
- 'Sundial' series: A varietal that blooms earlier and tolerates cloudy days and cool weather better than many other varieties.
Pruning Moss Rose
At the most, moss roses need light pruning, and only if you live in a zone where they can survive year-round. The best time to do so is in the early spring before new growth begins to emerge. Remove any growth that looks dead or diseased—you can also thin out a dense plant to improve air circulation, which can reduce the risk of fungal disease. Deadheading the plant's spent blooms is not necessary.
Propagating Moss Rose
Like most succulents, moss roses can be easily propagated through cuttings. In fact, the cuttings will root readily and most gardeners find great success with propagation methods. Here's how:
- Using sharp, clean shears, make a cutting from a mature, established "mother" plant that has bloomed for at least one season. The cutting should be at least 4 inches in length and include at least one node.
- Remove all leaves and flowers from the cutting.
- Place the cutting in a small bowl of water as you prepare the rest of your materials.
- In a small pot, combine a moist but well-drained mixture of sand, soil, and peat moss.
- Bury the stem cut-side down at least three inches deep into the soil.
- Cover the pot with a plastic bag or some other means of trapping humidity.
- Move the cutting to a spot that gets bright filtered light and maintains a temperature between 65 and 75 degrees Fahrenheit. Water occasionally, just until the soil is moist. Cuttings should root within about two weeks, at which point they can be cared for as typical moss roses.
How to Grow Moss Rose From Seed
If you're growing moss rose plants from seed, you can either start them indoors six to eight weeks before your projected last frost date or plant them in the ground after your area's last frost. Add the seeds to slightly moist soil and barely cover them—they need light to germinate. Maintain slight soil moisture until the seedlings emerge (germination should take about two weeks), then water the plants only when the top inch of soil is dry. Keep the seedlings by a bright window if you're growing them indoors.
How to Get Moss Rose to Bloom
If you're struggling to get your moss roses to bloom (or they're not producing bountiful enough blooms for your liking), the problem almost always lies in the soil's moisture level. Moss roses really dislike wet or soggy soil, and being planted in a medium that retains too much moisture will cause them to cease blooming. Try stepping back your watering cadence—you can also repot your moss roses into a container, which naturally drains faster than the ground would. Additionally, clay or terracotta pots can help wick excess moisture from the soil.
Another hugely important factor when it comes to having your moss rose bloom is ensuring it gets the proper amount of sunlight. Moss roses like ample light and hot conditions, and even an hour or two of shade can make the difference between bountiful blooms and barely any buds. Make sure your moss roses get at least six to eight hours of direct sunlight daily. If growing in a garden with other plants, you may even need to trim back nearby specimens so they don't block the light.
Are moss roses easy to care for?
Generally, moss roses are straight-forward to care for. As long as you plant them in a location that grants them enough sunlight and cultivate the proper soil conditions, caring for the plant is no issue.
How fast do moss roses grow?
Moss roses grow quickly and will often form a mat of growth within their first season.
Can you grow moss roses indoors?
You can start moss roses indoors but they should be transplanted outdoors once the weather allows. Moss roses do not sustain well indoors long-term.