UNITED STATES—Flowers bloom for pollination. It is that simple. Most rely on wind to disperse their pollen. They are more abundant than colorful or fragrant. More prominently colorful and fragrant flowers rely on pollinators. Their color and fragrance attract preferred pollinators, such as insects, birds or bats. Such flowers sustain their pollinators with nectar or surplus pollen.

More than pollinators appreciate their diligence. Almost everyone who enjoys gardening enjoys floral color and fragrance. Cultivation of naturally appealing bloom began several thousand years ago. Selection and breeding most likely began relatively soon afterward. Ultimately, during relatively modern history, hybridization began getting too complicated.

Pollinators were not a priority during such processes. Because most ornamental flowers produce no usable fruit, pollinators are unimportant. Because of extensive hybridization, many ornamental flowers are sterile anyway. Floral color, fragrance and various tangible attributes are more important. Modern bloom appeals more to people than to pollinators.

Some flowers no longer serve their original purpose.

A few modern flowers now confound their original pollinators. Some types of insects can die of exhaustion while trying to ascertain them. These insects may recognize floral color or fragrance but not strange floral structure. A few modern flowers are too frilly for access. Some attract pollinators without providing enough nectar or extra pollen to sustain them.

Several exotic flowers with less or no breeding distract pollinators with their abundance. Lemon bottlebrush blooms very abundantly and is still common within some landscapes. Blue gum eucalyptus is naturalized in parts of California. Both attract monarch butterflies that native species rely on. Native ceanothus must instead rely more on other pollinators.

Furthermore, a few pollinators actually disrupt native ecosystems. Honeybees, although very important to local agriculture, are not native. They arrived in San Jose in 1853, from where they dispersed throughout the West. It is now impossible to assess their influence. Even seemingly beneficial influence is unnatural and therefore ecologically detrimental.

Highlight: Tropical Hibiscus

Hummingbirds and butterflies are quite fond of tropical hibiscus, Hibiscus rosa-sinensis. They are attracted to the bright yellow, orange, red, pink or white color of its bloom. They stay for the syrupy nectar that they find deep within the flowers. Tropical hibiscus attracts pollinators rather efficiently, but almost never generates seed. Most cultivars are hybrids.

Tropical hibiscus flowers are not overly profuse but are about three or four inches broad. Fancy hybrids that bloom with broader flowers are not as vigorous as more typical sorts. Most cultivars bloom with somewhat ruffled single flowers. Some bloom with more ruffled double flowers. Both types of flowers have five garishly flaring petals. None are fragrant.

Tropical hibiscus grows as evergreen shrubbery about 6 to a bit more than 10 feet tall. Pruning to remove congestion of inner growth promotes healthier outer growth. Besides, whitefly and scale insects often proliferate on crowded foliage. Leaves are mostly two to five inches long and two to three inches wide. Bloom continues from summer to autumn, mostly with warmth.

Tony Tomeo can be contacted at tonytomeo.com.