Semps and Sedums require about the same care. The difference is that Sedums are shipped with some soil on the roots while Semps are shipped bare root. Also you may want to encourage bloom on Sedums. So you can fertilize them a little more than Semps. You should not encourage blooms on Semps because they die after blooming.
When to Plant
In areas with very cold winters, Semps should be planted from spring through August so that the roots are well established by winter. In milder climates the planting season may be extended. Volcanic cinders or gravel make an attractive top dressing and are some protection for the plants. If you have any concern as to whether they are well enough established going into the first winter, you can place rocks around them. In fact, they are perfect rock garden plants and very pleasing results can be obtained by tucking them in and about rocks, driftwood and crevices.
When your semps arrive, they will have been in the dark for a few days and may be open wide in an effort to collect more light. Plant them as soon as possible in the area where they are to be grown or in holding pots if you are not ready to plant them in the garden.
The soil should be lightly moist, and watering should be withheld for 5 or 6 days. If they are to be planted in full sun, introduce it gradually over a period of about a week. This can be accomplished in a number of ways. Perhaps the simplest is to cover them lightly with leaves, pine needles or straw and remove the covering a little at a time while the plants adapt.
We grow them in the open here. They can thrive in filtered or part day sun as well. In desert areas semps must be protected from summer sun. If your area has very hot, humid summers they will need good air circulation as well as protection from very hot sunshine. Avoid very dense shade. It can result in loss of color and distortion.
Soil and Drainage
Sempervivums will adapt to most soils. We use a good planter mix cut with sand. This is quite a loose mixture and requires that we water more frequently during our very dry spring weather, but it relieves any concern about drainage during our heavy and regular summer rains and during snow melt. Semps prefer moist soil but will not tolerate standing water. Drainage is perhaps the most important consideration in choosing a planting location. If drainage is a problem, they can be grown in raised beds or containers. Cover only the roots with soil being careful to not cover leaves or offsets.
Aphids will sometimes be seen on the plants. This happens usually when there is a flower stalk. Insecticidal soap is adequate for this problem. If you should find problem pests such as mealy bug, a good systemic spray such as Orthene¨ should be used. Do not use Malathion or the like. The plants of the Crassulaceae family cannot tolerate it.
You may work in a little bone meal when planting. The semps can then be fertilized once or twice during the spring/summer growing season. Use an all-purpose fertilizer. Mix according to label, only cut to half strength. For instance, use fish emulsion mixed one-half Tblsp. rather than 1 Tblsp. per gallon of water. We do not recommend fertilizing during the first year other than the addition of bone meal to the soil.
When a semp rosette is 2 or 3 years old it may send up one or more blooming stalks. After flowering, that rosette will die. There is nothing that will prevent it. However, it will by then have produced many “chicks” to make up for it. You can propagate these chicks, as detailed below, to start more plants.
Sempervivums : EXPERIMENT with the offsets. You can snip off the “chicks” and start them by pressing them lightly into soil. However, we recommend that you wait until they develop their own roots while attached to the “hen”. Then break or snip the stolon, lift the chick from the soil and plant it elsewhere.
Sometimes semps will “drop” their offsets. Unless very immature, chicks will root simply when placed on soil or sand.
Jovibarbas: Just scatter jovibarba rollers as this is their method of reproducing. They will right themselves and take root.
Jovibarba heuffelii multiply from one central root. To separate them, you must dig up the entire plant and slice them apart with a clean knife. Then let the wounds “heal over” for up to a week in a cool, dry place before replanting. Be careful with the watering.
Sedums: Separate leaves or segments of sedums to propagate. Leave sedum pieces for up to a week in cool, dry place to heal over. Then plant them in sand, and keep them moist till rooted. Do not over water.
Color and Size
Color and size descriptions in our catalog are according to the plants grown in our garden and should remain basically the same. You may discover different results according to light, soil or other environmental variations in your location. This is why it is fun to experiment by planting the offspring in various places about your garden or in containers.