By Nan Sterman
It’s simple to grow beautiful roses in Southern California’s dry, Mediterranean climate. Just ask one of the world’s leading rosarians, Tom Carruth, the curator of the famous rose collection at the Huntington Library and Gardens in San Marino, California. He’s bred and patented 80 varieties of roses, including the well-known ‘Julia Child’.
Carruth cares for hundreds of roses, so there’s no time for pampering -- and no point either. “Grow roses like any shrub in our Mediterranean climate,” he says, “Train them to have deep roots to tolerate drought.”
Carruth waters established roses deeply but only occasionally, allowing soil to dry between waterings. He uses soaker hoses or forms a basin around each plant to direct water to the root zone. Fill the basin, let drain, and repeat. Clean foliage by spritzing with water once a month (preferably in early morning so leaves dry before nightfall).
Choose roses with sturdy, intact roots. Plant potted roses anytime, but put in bare-root roses by the first week of February. Plant into well-amended soil, setting the graft union (a swollen area where cultivar is grafted to rootstock) at ground level to touch the soil. Water well, then layer on 3 or 4 inches of chunky, organic mulch. Fertilize with a balanced fertilizer two or three times through the growing season, starting once new growth is 6 inches long.
Carruth recommends pruning between January 15 and February 15 -- before new buds appear. Reducing the plant by about half encourages new wood for lots of flowers. Climbing roses are a notable exception to hard pruning. This ‘Joseph’s Coat’ climber, for instance, grows 8-12 feet tall. But it’s the flowers that really stand out with a blend of yellow, pink, apricot, and orange changing over time.
Spraying isn’t necessary, says Carruth, adding that he hasn’t sprayed a rose in 18 years: “If you have the balance of nature behind you,” beneficial insects will come in to take care of pests.
Carruth favors floribundas for their compact size and big, colorful flower clusters. Some are even fragrant. There are native roses such as Rosa californica and Rosa minutifolia, which are both thorny, dry-ground species with simple, pink flowers. And there are always the popular and highly floriferous groundcover roses to fall back on.