Hardy succulents are a delight to those who consider themselves to have a black thumb. Most are hardy to USDA Plant Hardiness Zone 5, -20 to -15 °F (-28.9 to -26.1 °C), and some can survive in temperatures as low as -40 °F (-40 °C). These plants easily propagate and are low maintenance. They can be severely neglected and still thrive. The only growing requirement that cannot be deviated from is that hardy succulents must be planted in well-drained soil to ensure adequate drainage.
Do you live in an area where your soil has a lot of clay? No problem, just amend the soil with 50 % or more pumice, perlite, coarse grit, or sand, and you will be ready to plant hardy succulents. Full sun planting is recommended to reveal the most robust colors of hardy succulents.
A 5-10-10 fertilizer is recommended 1 to 2 times during spring for optimal growth. Bone meal (a mixture of ground animal bones, 4-12-0) can be applied to the soil anytime. A bone meal is basically a boost of Phosphorus, which promotes root and tissue growth.
Common hardy succulents often found in local greenhouses include Sempervivum, Sedum, and Delosperma. The rarer genus includes Rosularia and Orostachys, and you usually have to scour specialty greenhouses or rock garden suppliers to find these plants.
Sempervivums, commonly called Hens and Chicks, are popular hardy succulents, and this word translates to mean "live forever." There are over 3,000 cultivars with many different textures and forms. Most Sempervivums produce tight clumps that form mounds, and their colors are not only shades of green but can also include brown, purple, silver-blue, red, orange, yellow, and delicate pinks. Sempervivums propagate by producing offsets (chicks), which can be left attached to the mother plant (hen) or removed to start a new plant elsewhere.
Sedums, commonly called Stonecrops, have two primary shapes. They are shaped like a low spreading ground cover or a two-foot (60 cm) shrubby mound. They look great in the landscape and containers mixed with other plants. Colors range from smoky blue to rich burgundy. Provided it gets enough light, Sedum will produce flowers. Propagation occurs easily by removing and replanting the plant's offsets, replanting cuttings, or allowing the plant to self-seed.
Delospermas are the favored "Ice Plants." They are often used as ground cover and are ideal for planting in rock gardens. These attractive succulents have fleshy green foliage, low spreading stems, and bright shimmering flowers that add color and texture to gardens. You can reduce reflected heat and glare by planting them in areas covered with gravel mulch.
Two rare and interesting hardy succulents are Rosularias, which resembles small Hen and Chicks growing in dense clusters, and Orostachys, often called Dunce-Caps. Both look similar to Sempervivum but are, in fact, closely related to Sedum. These two interesting plants take a little more effort to grow but are worth it.
If you choose to grow hardy succulents in containers, more attention is needed for drainage. A typical succulent container mix is half compost and half drainage material such as perlite, coarse sand, vermiculite, or pumice. Adding bone meal or a low nitrogen slow-release fertilizer such as 2-10-10 is also recommended when planting in containers.
Although all of the above plants enjoy full sun and are drought-tolerant, succulents are not cacti, and to remain their healthiest, they should be watered weekly if there is no rain in the forecast. If your succulents are located in the shade, less watering is needed. Ideally, the soil should dry thoroughly between waterings. The most common pests for succulents are aphids. Rinsing the plant with a strong stream of water is often enough to dislodge the aphids.
Another beautiful use of hardy succulents is in living art. This is the placement of succulent cuttings in a shadow box for vertical display. The cuttings take root after a few weeks, and the shadow box is then hung or leaned against a wall outside. As long as some shelter is provided in the winter, such as being placed in an unheated garage, the succulents in your living art will continue to thrive once spring arrives. If you start your succulent plantings this year, you will be well on your way to having enough cuttings to make your living art next year! Hardy succulents can be grown by anyone, even those who profess to have a black thumb.
Source: extension.psu.edu
Links
- Succupedia: Browse succulents by Scientific Name, Common Name, Genus, Family, USDA Hardiness Zone, Origin, or cacti by Genus