UNITED STATES—Tall Victorian houses make long shadows. Lower ranch houses make shade with broad eaves. Awkwardly big modern homes shade more of their disproportionately small gardens than the others, especially since they have such tall fences to compensate for their minimal proximity to other homes. Even the sunniest of home gardens have some sort of shade.

Like various architecture, various shade trees make different flavors of shade. Silk tree, honeylocust and silver maple make broad shadows of relatively light shade. Because they are deciduous, they allow most sunlight through while bare in winter. Southern magnolia, Canary Island pine and Canary Island date palm make darker shade throughout the year.

Spots that are shaded only by the west side of a fence get warmer afternoon sun exposure than spots that get eastern exposure in the morning. Plants that are only shaded in the morning, therefore need to tolerate both warm afternoon exposure and partial shade. Eastern exposures are easier to work with, since most plants that tolerate a bit of shade also like to be sheltered from harsh afternoon exposure.

Because fences lack eaves, southern exposures lack shade, and may enhance exposure by reflecting glare and heat. Southern exposure against houses and garages is determined by the height and width of the eaves. Light colors reflect more than darker colors. Northern exposures are of course the shadiest.

Whether for shade of sunny exposure, plants need to be selected accordingly. Bougainvillea, ceanothus and other plants that like good warm exposure with plenty of sunlight will not do much if shaded. Kaffir lily, hosta, rhododendron and various ferns that prefer partial shade can get roasted if too exposed when the weather gets warm and dry (with minimal humidity).

Eastern redbud, sweet bay, Oregon grape, Heavenly bamboo (nandina), various hollies, various podocarpus and both English and Algerian ivies are some of the few plants that are not too discriminating about their exposure, and will be just as happy with partial shade as with full exposure. Hydrangea, camellia, fuchsia and aucuba are nearly as agreeable, but will get roasted by harsh exposure enhanced by reflected glare from walls or pavement. All palms tolerate shade while young, but adapt to full exposure as they grow above what shades them.

Shade can change as the environment changes. Sun exposure increases if a tree or building gets removed. Remodels or newer and higher fences can increase shade. Even without such obvious modifications, large shrubbery and trees make more shade as they grow.

Highlight: Rockrose

The few rudimentary rockroses that were available years ago have been bred into too many cultivars to keep up with. Some of the traditional types can get a few feet tall, with delightfully irregular growth, and flowers that are almost three inches wide. Most of the modern types are relatively dense, low and mounding, like a deep ground cover, with smaller but more profuse flowers. Most bloom pink. Some bloom white. After the initial spring bloom phase, a few flowers continue to bloom sporadically through summer. The grayish and aromatic foliage is not as impressive as the bloom. Rockroses want well drained soil and good warm exposure.