RHAPSODY IN BLUE AND PURPLE IS HERE.

Byline: JOSHUA SISKIN

In the Valley, no botanical event is more delightful and defining than the hazy mauve-blue bloom of jacaranda trees, a sure sign that summer has unofficially arrived.

In the forests of Brazil, Argentina and Peru, jacarandas are known to flower with special intensity following prolonged dry spells. This would explain the heavy flowering of our jacarandas at the present moment, considering the minuscule amount of rain during the past year.

The full glory of jacaranda trees may be best appreciated along Stansbury Avenue in Sherman Oaks. You wonder why more Valley parkways are not planted with these beauties. True, jacarandas can grow to more than 60 feet and their brittle branches are prone to break; their roots grow into water lines and push up sidewalks. Yet jacarandas, like California sycamores and coast live oaks, are worth the maintenance they require because of the elegance and opulence they bring to any neighborhood.

In addition to the jacaranda, there are many plants with blue or mauve flowers that come into their own in warm weather. The most famous of these is agapanthus, also called lily-of-the-Nile, a stalwart of the perennial bed that's virtually indestructible in full to half-day sun.

Two problems associated with this plant are snails and mealy bugs (sticky, cottony white insects). To prevent mealy bugs from nesting, thin out your clumps of agapanthus on a regular basis.

One of the most heat-loving ground covers is Scaevola, an Australian plant with small fan-shaped mauve flowers. With its trailing growth habit, scaevola is also a classic subject for terra cotta pots and hanging baskets.

Penstemon or beard's tongue is a California native perennial with trumpet flowers that appear in many colors, including mauve and purple, and requires a minimum of water to grow well. It is nicely complemented in the landscape by woolly blue curls (Trichostema lanatum), a hydrophobic native with bluish-purple flowers. You should also include three sturdy standbys called Mexican sage (Salvia leucantha), statice (Limonium perezii), and blue hibiscus (Alyogyne Huegelii) in your blue and purple flowered palette of water-thrifty plants.

Last but certainly not least would be the butterfly bushes (Buddleia species). They do not get the recognition they deserve, considering their massive, fragrant flower wands, up to a foot in length. Butterfly bushes feel at home in an English garden, a gray-leafed garden, a butterfly garden or a fragrant garden. They contrast admirably with the bright green foliage of more-common shrubs such as privet (Ligustrum) and mock orange (Pittosporum).

TIP OF THE WEEK: Palm trees, especially those in containers, will develop yellow fronds and scorched leaf tips when not fertilized properly. Ask for specially formulated palm tree fertilizer products at the nursery. Citrus also benefits from custom mineral blends that are typically packaged as ``citrus and avocado fertilizer.''