Mat Forming with Dense Clusters, Part or Filtered Sun
Rosularia (ros-uh-LAIR-ee-uh) & Prometheum (pro-MEE-thee-uhm) are mat-forming, cold hardy succulents that are difficult to find in most collections. They have the classic rosette shape and low maintenance needs of Sempervivum (Hens & Chicks) but are unique in their ability to bloom repeatedly. Like their close relatives Sedum (Stonecrop), Rosularia & Prometheum make a colorful and easy to grow ground cover, even with poor soil and infrequent watering.
Form: Rosularia & Prometheum rosettes stay under 4” tall and spread as a dense mat by sending out new offsets on stolons.
Foliage: Their fleshy leaves are a soft green lined with dusty rose, yellow, or purple. These colors flush brightest with some sun and heat stress.
Flowers: In late spring and summer, bloom stalks erupt from the mat of rosettes, unfurling tiny yellow and white star-shaped flowers.
Light: Rosularia & Prometheum grow best outdoors in full to partial sun. Indoor growing is more challenging, but possible if plants are kept near a very sunny window or under a dedicated grow light.
Soil: Whether in the ground or a container, Rosularia & Prometheum need a well-draining, sandy soil like cactus/succulent potting mix. If you choose to fertilize, use a slow-release, low Nitrogen (5-10-10) fertilizer and apply it in the spring.
Water: Rosularia & Prometheum have low-water needs and will rot if over-watered. Water deeply but infrequently, giving enough time for the soil to dry completely. In winter, the shorter, colder days signal them to slow their growth, during which time they need even less water. If planting in a container, it’s best to use one with a drainage hole (more info).
Hardiness: Most species of Rosularia & Prometheum are cold hardy down to -20F (zone 5) and will survive deep winter freezes protected under a blanket of snow (more info).
Propagation: You can cut the offsets from their stolons to transplant. Rosularia & Prometheum can also be regrown from leaf cuttings or left alone entirely to self-propagate.
NOTES FROM THE NURSERY
Rosularia & Prometheum are excellent choices for rock gardens, ground cover, miniature/fairy gardens, and indoor or outdoor containers. Try tucking them into the crevices of a stone retaining wall and prepare to be amazed.
The most common challenge for Rosularia & Prometheum is over-watering. Always err on the side of less frequent watering and provide great drainage. If planting in containers, use pots with drainage holes and a gritty, well-draining soil.