In the large Senecio genus of over 1,000 species, there are about 100 succulents used as garden plants in warmer climates and as container-grown plants in other regions. Some are large shrub varieties, but many are trailing plants used as spreading groundcovers or in hanging baskets. There are also upright species.
The leaves can be deep green, bluish, or even striped, with considerable variation in the leaf shape. Some are round, some are banana-shaped, and some stand upright. The flowers range from red or white spires to yellow daisy-like flowers, forming clusters on long stems and persisting for weeks. However, it is the foliage that interests most gardeners.
The best time to plant Senecio is in the early fall before the new growth period starts.
All Senecio species should be considered toxic to humans and animals.
|Common Names||Senecio (varies by species)|
|Botanical Name||Senecio spp.|
|Plant Type||Perennial, succulent|
|Mature Size||5 in.-3 ft.|
|Sun Exposure||Full, partial|
|Bloom Time||Varies by species|
|Flower Color||Varies by species|
|Hardiness Zones||9-12 (USDA)|
|Native Area||South Africa|
|Toxicity||Toxic to humans and pets|
Generally the growing conditions for Senecio plants grown outdoors year-round in warm climates are similar to those of potted plants. Established plants are extremely drought-tolerant and low-maintenance.
In hot climates, the plants prefer bright indirect light whereas in cooler climates, they should get full sun.
The plants aren't particular about soil pH and do fine in the neutral range (6.0–7.0). More importantly, make sure the soil is well-drained and on the sandy side. For potted plants, use a fast-draining succulent or cactus soil mix.
As succulents, these plants have excellent tolerance for drought. For most types, allow the roots to dry out completely between waterings. Soaking in water will cause the roots and plants to turn mushy.
Temperature and Humidity
Most varieties thrive in USDA Hardiness Zones 9 to 12. As with the majority of succulents, they're heat-tolerant. A few Senecio species can withstand brief periods of cold or dampness, but prolonged exposure to cold will turn them to mush.
Since Senecio plants grow in sandy soil, the nutrients will need to be replenished. Fertilize annually, but lightly. Too much fertilizer can cause an abundance of leggy growth.
Types of Senecio
There are many dozens of succulent Senecio species. Here are just a few of the well-known varieties:
- Lavender steps, propeller plant (S. crassissimus): This low maintenance variety is an easy grower that can handle some frost. It features bluish, flattened leaves on an upright plant. It grows 18 to 24 inches tall with an 18-inch spread, and is hardy in USDA zones 10 to 11.
- Cocoon plant (S. haworthii): "Cocoon" refers to the shape of the gray leaves, which form a prostrate bush but do require periodic renewal. This plant grows to 1 foot high with a spread of up to 3 feet, and is hardy in USDA zones 9 to 11.
- String of bananas (S. radicans): This variety is more tolerant of shade and moisture. It features puffing, crescent moon-shaped leaves that punctuate long stems. It grows 6 to 12 inches tall with a similar spread, and is hardy in USDA zones 10 to 12.
- String of beads, string of pearls (S. rowleyanus): This plant is comprised of dangling stems of round leaves, and does well with minimal watering. it is a trailing plant that can extend 3 to 5 feet, and is hardy in zones 9 to 12. It is often used in hanging baskets.
- Blue Chalksticks (S. serpens): This variety has short, steel-blue, tubular leaves. It grows 12 to 18 inches tall with a spread of 18 to 24 inches, and is hardy in zones 10 to 11.
- Blue Chalksticks (S. mandraliscae) is similar to S. serpens but a more vigorous grower with pencil-like leaves.
Other than removing dead or diseased foliage, Senecio does not need much pruning. To prevent floppiness in taller varieties, you can prune them back to where the stem is firm.
Rooting cuttings is the easiest and fastest way to propagate Senecio plants. This is best done during the growing season between autumn and spring, While the size of the cutting depends on the species, the overall process is the basically the same as for planting succulent cuttings:
- Take a cutting and let it callous over for a few days.
- Dip the cutting in rooting hormone and plant it in a container filled with well-draining potting mix.
- Start watering only once roots have developed.
How to Grow Senecio from Seed
Because Senecio is so easy to propagate from cuttings, it is the most commonly practiced propagation method. Senecio is rarely sold as seeds.
Potting and Repotting
Smaller varieties of Senecio grow well in containers, either combined with other plants or alone. Use a fast-draining succulent or cactus soil mix and plant it in a pot with good drainage holes, ideally terra cotta or unglazed ceramic.
The need for repotting depends on the growth rate of the variety. Repot when the root system fills the pot, or when roots start to grow out of the drainage holes.
In colder climates, potted Senecio plants need to be brought indoors during the winter months. Give the plants the brightest, sunniest location you can find and water them when the soil feels dry to the touch.
Common Pests and Plant Diseases
Is Senecio an indoor plant?
It depends on the species. Some low-growing types such as String of Pearls are mostly grown as a houseplants, while taller ones such as Blue Chalksticks are planted outdoors as groundcovers and rock garden plants in warmer climates.
Is Senecio vulgaris invasive?
Common groundsel (S. vulgaris) is listed as an invasive plant in parts of the Pacific Northwest, the southeastern United States, and Alaska.
Do Senecio plants go dormant?
They do but not in the winter. Senecio are winter growers that go dormant in the summer.