The rhododendron garden at the San Francisco Botanical Garden is coming into bloom, and its designer, Georgia Madden of Feyerabend & Madden Landscape Design in Emeryville, recommends these early-flowering, easy-to-grow species: Rhododendron arboreum, a small treelike accent with red flowers and large leaves; R. ‘Noyo Dream’ for its overall form and creamy pink blossoms; and R. ‘Sabrina Adler’ with clusters of pale pink to white flowers for a vigorous but not too large foundation planting. These and many others are available from Sonoma Horticultural Nursery.
As soon as frosts are past, plant culinary herbs such as chives, cilantro, dill, mint, oregano, parsley, rosemary, and thyme in a sunny part of the garden.
Start tomato seeds indoors on a sunny south-facing windowsill early in the month, or about six weeks before the last expected frost. Organically grown seeds of 600 heirloom tomato varieties are available from TomatoFest. Among site founder Gary Ibsen’s favorites for Northern California are pink ‘Julia Child’, purple-black ‘Black Prince’ and ‘Paul Robeson’, red ‘Aussie’, and yellow-orange ‘Kellogg’s Breakfast’.
Peas and potatoes like the cool growing conditions of early spring. In coastal areas, plant early in the month. In other areas, plant peas six to eight weeks before theast frost date, and potatoes four to six weeks before the last frost date.
You might do a double take: Are these exotic roses? Miniature peonies? Nope. They’re Maché ranunculus. With luscious petals that look like layers of brightly pigmented tissue paper, the 4-inch-wide blooms sit atop sturdy stems and foliage. They’re available in seven colors, including the rose and purple pictured here. Find them as blooming potted plants in 4-inch containers at nurseries this month and next. Treat Maché like an annual and remove plants when blooms fade, typically as summer arrives.
Almost all plants, including annuals, perennials, trees, and lawns, will appreciate a boost of nitrogen now as spring growth starts, so feed with an all-purpose fertilizer. Wait until azaleas, camellias, and rhododendrons have finished blooming before feeding them; then use a formula labeled for acid-loving plants.
To make maximum use of small vegetable planting areas, double-dig and amend the soil with compost so you can grow your plants closer together and water less.