Selecting and growing acid-loving plants
Without question, these plants are among the most beautiful of all flowering shrubs. Many are planted here and most struggle to survive. The reasons are simple. These acid-loving plants need rich, well-drained garden soil and a constant moisture supply. For the most part, we have poor, dry, alkaline soil with little or no drainage. Very low humidity, scalding sun and hot, drying winds cause more problems. The maximum sunlight and minimum rainfall that many of us enjoy are very tough on these popular plants. With this knowledge and some careful planning, you can successfully grow these plants in the desert.
Following are some brief descriptions of each variety with some handy planting and maintenance tips. A list of plants commonly grown in medium to full shade is also provided. For complete information and variety descriptions, consult the Sunset Western Garden Book.
AZALEA are small-leafed evergreen species of rhododendron that blooms in early spring. A wide range of colors are available, including red, white, pink and lavender. Plant sizes range from compact dwarfs to 4-5 foot hybrids. They are often grown in patio containers and hanging baskets. Give these plants a north or east exposure in the garden. An ideal location would be filtered shade beneath or near tall trees, especially pines. Remember, these plants will not take full sun in our climate. Pinch tip growth after flowering to keep compact shape.
Prepare the soil with a 50-50 mixture of Paydirt™ Planting Mix and native soil. Add 3-4 handfuls of pre-moistened peat moss to the mixture. Good drainage is critical, but so is moisture retention. If your planting location won’t drain properly or dries out too quickly, consider a raised bed to meet these requirements. When planting in pots, use a complete all-purpose potting mix. Amend the mix lightly with pre-moistened peat moss.
Plant Azaleas with top of the root ball slightly above soil level. Do not bury the plant or allow soil to accumulate around stems. Water them thoroughly with a solution of Dr. Q’s® Plant Tonic and water. Apply a 2-inch layer of bark mulch or pine needles. Because of shallow surface roots, do not cultivate around the plants. Raised beds or containers are great for these plants.
Water and fertilize azaleas regularly. More frequent watering may be needed in raised beds. Flush containers with the hose at least twice a year to remove excess, water-induced salts; run the hose for several minutes each time. Use a fertilizer rich in sulfur like Dr. Q’s® Rose & Flower Food or Gold Dust. Feed when new growth is first noticed in spring, at bloom time, and monthly thereafter until August.
CAMELLIA. While there are dozens of camellia species and even more hybrids, the two basic types most commonly found in our area are Japanese Camellia (Camellia japonica) and Sun Camellia (Camellia sasanqua). Both varieties are evergreen and make excellent container specimens for patios or gardens. Flowers range from single to fully double in all colors from white and rose to pink and red. Japanese types are taller, frequently exceeding 6 feet, and flower most heavily from fall through winter. They make excellent espalier, bonsai and ground cover subjects as well. Don’t be fooled by the name! All camellias need protection from direct and reflected afternoon sun, as well as hot winds. Best planting exposures are north and east in medium to full shade, or early morning sun.
Prepare the soil with a 50-50 mixture of Paydirt™ Planting Mix. Add Dr. Q’s® Gold Dust Starter Fertilizer according to package instructions. Make sure your planting site has excellent drainage. If planting in containers, use an all-purpose potting mix like Filthy Rich™. Redwood tubs or half-barrels make the best containers for camellias. Add Paydirt™ to soil surface as it settles.
Planting Camellias so the trunk base is above the soil line. Water them thoroughly with a solution of Dr. Q’s® Plant Tonic and water. Never let soil build up around the trunk. Keep roots cool in summer with a 2-inch layer of bark mulch. Raised beds or containers are great for these plants.
Water and fertilize regularly. Camellias like excellent drainage and moist soil. Flush salts from the soil with a slow, deep hose soaking, or several hours of drip irrigation in early and late summer. Fertilize with an acid fertilizer like Dr. Q’s® Rose & Flower Food or Gold Dust just after bloom and again 6 weeks later. Treat with iron chelates like Ironworker or Kerex to prevent chlorosis.
GARDENIA. These evergreen shrubs grow to 5-6 feet tall. They are temperamental and difficult to grow in alkaline desert soils, performing best when grown in containers. If trying in the garden, heavily amended, raised beds are your best bet. Dwarf varieties are good hanging basket subjects. Mystery is a well-known variety with double flowers from May through July. All varieties have intensely fragrant blooms. Excellent drainage and rich, most soil is necessary for success. Keep gardenias out of direct sunlight. North or east exposure in filtered to medium shade is best. Gardenias like heat but need protection from frost and freezing. Prune lightly to shape as needed.
Prepare the soil with a 50-50 mix of Paydirt™ Planting Mix and native dirt. Add peat moss if necessary to insure water retention while keeping good drainage. Use an all-purpose potting mix for container subjects. Add Dr. Q’s® Gold Dust Starter Fertilizerper package directions.
Plant gardenias high, like azaleas and avoid competition from other plants. Water them well with a solution of Dr. Q’s® Plant Tonic and water. Mulch soil surface with a 2-inch layer of fine or medium bark and don’t cultivate. A layer of peat moss makes good container mulch. Raised beds or containers are great for these plants.
Water and fertilize gardenias regularly. Keep soil moist and leach salts through heavy, slow soaking 2-3 times during the summer. Feed with an acid-based fertilizer like Dr. Q’s® Rose & Flower Food or Gold Dust every 4 weeks from March through October. Treat with iron chelates as needed to combat chlorosis.
Dealing with our high pH water
Even though you may start your acid loving plants with well amended soil where the pH has been balanced, because our tap water generally has a pH of 8.2 and above, you will need to treat the soil periodically to keep the pH down. A great product to help you accomplish this is Con-Grow (see Gardening Tip # 1016).
OTHER ACID-LOVING PERENNIALS AND SHRUBS
Perennial flower varieties like Hydrangea (Blue), Orchids, Rhododendrons, Amaryllis, Bilbergia, Christmas Cactus, Creeping Fig, Croton, Prayer Plant, Rubber Plant, Tradescantia and of course Photinia should be treated in much the same way as the shrubs discussed above.
Ask a friendly Star Nursery associate if you have additional questions about plant selection, location, planting and care.