Tucson, a southern Arizona city nestled among four mountain ranges, is blessed with a large variety of plant life. Choose native Tucson-area plants that bloom at different times of year, so your garden will always have color. All of them are tolerant of the summer heat and limited rainfall of this desert environment. Many of Tucson's white flowering shrubs are hauntingly fragrant, adding another delightful dimension to the garden.
Night-blooming cereus (Peniocereus greggii) is a shrubby member of the cactus family. The plants redeem their otherwise scraggly appearance in spectacular style on June evenings, when huge waxy white flowers fill the air with fragrance. Each bloom, measuring up to 6 inches across, lasts only one night. Spiny oval red fruit follows the flowers. Tubers weighing between 5 and 15 lbs. produce the shrubs, which can reach 7 feet high.
Night-blooming cereus, says the U. S. Forest Service, has become endangered throughout much of its range because collectors dig up the tubers for resale. Tuber collection isn't even necessary, because plants will propagate easily from cuttings that are allowed to heal in a shady spot before rooting in sand. These shrubs need dry, sandy or gravelly soil and nearby shrubs for shade and branch support.
Fern acacia (Acacia angustissima), belonging to the pea family, is a small--up to 4 feet--shrub with narrow lacy foliage, slender stems and round, brush-like fragrant white flowers between June and September. Valued as much for its leaves as its blossoms, it's useful as a low perennial shrub or ground cover The tropical fern-like appearance makes it attractive around patios and pools. The foliage, however, dies back following hard frosts.
Loosen the soil within a 2-to-3-foot radius of the planting site, because fern acacia spreads by rhizomes. Choose a sunny spot with dry well-drained sandy or loamy soil, and water the plants well after transplanting them. Wait until new growth appears in the spring before cutting back the old.
Belonging to the verbena family, bee brush (Aloysia lycioides) has sweetly aromatic, deep green lance-like leaves and equally fragrant spikes of white flowers. Bee brush blooms most heavily between February and April, but also flowers after summer rains, and again in October and November. It grows up to 6 feet high and 8 feet wide, and makes an excellent hedge. It's also a great choice, says the Tucson Botanical garden, for butterfly gardens.
Plant bee brush during October or November in full sun to part shade. It blooms best in full sun. Water plants weekly in the peak of summer heat, then every other week until winter. Once they're established, a single monthly soaking will be enough. As its name suggests, fragrant bee brush is irresistible to bees. Place it where their nectar gathering won't be a problem.