Senecio is a large genus of plants within the daisy family, comprising over 1,000 species dispersed around the world, ranging from noxious weeds to highly prized garden perennials. Dusty Miller (S. cineraria) for example, belongs to this genus. Within the genus are included about 100 succulent species used as garden plants in warmer climates and as container-grown plants in other regions. Nearly all Senecio species should be considered toxic to animals. Some are large shrub varieties, but many are trailing plants used as spreading ground covers or in hanging baskets. There are also simple upright species.
The leaves on succulent Senecios are generally thick and fleshy. They can be deep green, bluish, or even striped, but there is considerable variation in the leaf shape. Some are round, some are banana-shaped, and some stand upright.
Senecio flowers form in clusters on long stems. The flowers persist for weeks—their shapes include red or white spires and yellow daisy-like flowers—but it's the foliage that interests most gardeners.
|Botanical Name||Senecio spp.|
|Common Names||Varies by species|
|Plant Type||Perennial succulents|
|Mature Size||Varies by species|
|Sun Exposure||Full sun to part shade|
|Soil Type||Sandy soil|
|Soil pH||6.0 to 7.0 (fairly neutral)|
|Bloom Time||Varies by species; bloom period is usually about 1 month|
|Flower Color||Varies by species|
|Hardiness Zones||9 to 12 (most species)|
|Native Area||Most succulent species are native to South Africa|
|Toxicity||Toxic to animals|
How to Grow Senecio Succulents
Senecio plants are generally planted from nursery plants or by simply embedding cuttings from a parent plant into soil. Seeds require warm temperatures (at least 55 degrees Fahrenheit) and constant moisture to germinate.
In the warm-climates garden, Senecio succulents should be planted in sandy soil in a location that receives very bright indirect light. When growing in patio or deck containers in cooler climates, they prefer a full sun location. Potted plants prefer a potting mix tailored for succulents.
Established plants are extremely drought tolerant. They do need some water during the summer, but be careful to not leave the soil wet for prolonged periods. Allow the soil to dry out between waterings in the winter, when the plants are somewhat dormant.
To prevent floppiness in taller varieties, you can prune them back to where the stem is firm. Early spring is an ideal time for trimming, dividing, and repotting.
Senecio plants prefer full sun when grown in cooler climates as container plants, but in very hot desert climates, the plants prefer bright indirect light. When brought indoors for the winter, give the plants the brightest, sunniest location you can find.
Senecio succulent plants aren't particular about soil pH. Something in the neutral range (6.0–7.0) should be fine. More importantly, make sure the soil is well-drained and on the sandy side.
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 Senecios 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.
Propagating Senecio Succulents
Cuttings are the easiest and fastest way to propagate Senecios. During the growing season, you can clip off a stem and root it in a pot of sandy soil to start a new plant.
Species of Senecio
There are many dozens of succulent Senecio species. Here are just a few of the well-known varieties:
- Vertical-leaf cenecio (Senecio 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 (Senecio 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 (Senecio 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/ pearls (Senecio 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 chalk stick/ blue ice plant (Senecio 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.
Few pests bother Senecio plants, but they can occasionally be affected by scale and mealybugs. If this happens, try treating with neem oil or an antibacterial soap solution.
In warmer climates, you can use Senecios as ground cover and rock garden plants. In colder climates, growing them in pots will allow you to bring them indoors as houseplants during the winter months. They grow well in containers, either mixed or alone.