Moss rose plants are a welcome addition to any garden, and with the right amount of time, effort, and know-how, you can grow them on your own! Moss roses, also known as portulaca, are the result of a 17th century spontaneous mutation of the Rosa Centifolia plant. As such, it is classified as an "old" rose and is notable for its strong scent, often not found in modern hybrid roses. Moss roses are summer-blooming roses and only bloom once a year, on the former year's growth. For this reason, don't expect blooms the first year. When it does bloom, it will do so in early summer and the blooms will last for several weeks.
The "moss" in moss roses refers to a moss-like growth on the stems and buds that appears lacy. This unusual characteristic makes this a rose to show off in your garden as well as your home. Planted near a walkway or in a rock garden, this plant will delight the eye with its unusual mossy characteristics and the nose with its full-bodied rose scent.
The moss rose was first discovered in the south of France in the late 17th century and quickly became a favorite of Napoleon's wife, the Empress Josephine. It is a hardy annual in colors of rose, red, pink, yellow, purple, and orange. The plants grow as miniatures, with blooms 4 to 6 inches tall, all the way to climbing roses suitable for trellises or archways. Like other old roses, moss roses grow on very prickly canes so be careful when handling.
In addition to seedlings, moss roses can also be propagated through cuttings taken from established plants.
Moss roses can be grown from seed in the spring. For earliest blooms, start the seeds indoors several weeks before the last frost date for your area. Seeds take about two weeks to germinate. When the ground is warm enough, set the plants in well-draining loamy or sandy soil. Moss roses thrive in average to poor soil and full sun. Use a general high-nitrogen fertilizer when planting and fertilize with a high-phosphorus fertilizer just before blooming. No other fertilization is needed. These plants do well in dry soil so don't worry about neglecting them. If planted in containers or hanging baskets, allow the soil to dry before watering.
To encourage new growth, pinch off the spent blooms as they wilt. Light pruning in the early spring to open up the plant and remove dead growth will allow better air circulation and help prevent fungal diseases. After the blooming season, prune lightly again to remove dead, damaged canes or any canes that cross each other. Do not remove too much of the current growth as that is where blooms will appear next year. Cut the remaining growth lightly, just at the tips. If the plant has become overcrowded, shape it by cutting side shoots back to outward facing buds. Do not crowd the plants.
Portulaca is a tough plant that thrives in areas of heat and drought. It is recommended for zones 4 through 9.
Like other roses, portulaca is susceptible to aphids, slugs, snails, fungus and rot. Use appropriate treatments as needed. To avoid some problems, plant in well-drained sandy soil or slightly raised beds.