Native plants such as the Encelia Calfornica on the left and right and the California Poppy, center, are being planted on Loma Ridge at the Irvine Ranch Natural Landmark. (SCOTT SMELTZER, Daily Pilot / April 16, 2011)

Spring has finally arrived. The sun is shining, and here in Southern California that means gorgeous wildflower blooms. Our state is home to an amazing array of plant diversity, ranging from redwoods to palms, pines to succulents. California is one of the most botanically rich regions in the world.

With this amazing diversity comes threats to our native plants, especially through urbanization. As more homes are built, more lawns need to be cared for. More boxwoods, camellias, petunias and geraniums mean less poppies, sages, lupines and oaks.

Our state's native plants ultimately give way to their cultivated cousins. Of course, that means more water, a resource that is already limited in the West.

In a much-celebrated move, the California state legislature last year declared the third week in April to forever be California Native Plant Week. Throughout the state, at gardens, nurseries, nature preserves and schools, the week ahead will celebrate California's diverse and wonderful native flora.

I encourage gardeners to participate in California Native Plant Week in your own individual way. Here are a few suggestions:

•With a friend, take a walk in a natural area and pay special attention to the plants. Perhaps your visit might be to Crystal Cove State Park, one of the preserves in Laguna Canyon, or even a bit further afield in the foothills of our Santa Ana Mountains. Orange County has dozens of choices. (Drop me a note if you want more suggestions — maybe I'll join you)

•Visit a local botanical garden or arboretum and visit the California native plant section. Rancho Santa Ana Botanic Garden, the premier native garden in California, is in Claremont, less than an hour away. Even nearer are the native plantings at The Fullerton Arboretum or the outstanding native garden at Golden West College in Huntington Beach.

•Participate in the Orange County Native Plant Garden Tour. This is a free, one-day self-guided tour of gardens throughout Orange County that feature all or mostly native plants. The date of this year's tour is May 7, but you can make your commitment to attend this week. Addresses and driving directions will be available the week before the tour. For information go to http://www.occnps.org.

•Attend Thursday's meeting of The Orange County Native Plant Society. The evening meeting in Irvine will feature artist and naturalist Laura Cunningham discussing California as it was before European contact, especially from a native plant perspective. The event is scheduled for 6:45 p.m., at The Duck Club, 5 Riparian View Way, Irvine.

•Plant a California native plant. Of the approximately 6,000 species that are native to California, how many are represented in your garden? Did you say "none"?

A few native plants incorporated in your garden will connect with its home — California of course. These plants are almost always low maintenance and water efficient and they often support native birds, butterflies and other wildlife.

Native plants are those species that have evolved within California's complex patchwork of ecological conditions, such as climate, soil type and rainfall. These plants continue to co-evolve with the native animals, insects and other wildlife that depend upon them as familiar sources of food, shelter and refuge. Additionally, as water becomes a more limited resource, native plants represent a quintessential choice to sustainable and ecologically sound gardeners.

California Native Plant Week is dedicated to the appreciation, education and conservation of California's fabulously diverse flora. This landmark bill was introduced by state Sen. Noreen Evans during the 2010 legislative session to help protect California's native plant heritage and to preserve it for future generations by raising awareness about our rich botanical diversity.

During the upcoming week, I hope local gardeners of any interest — whether it is flowers, roses vegetables, tropicals or succulents — take a moment to appreciate and celebrate California's native plants.

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Special Gardener's Note: This past week many areas of Southern California experienced hail. This was a very late occurrence locally and the soft, new growth of many plants may have been temporarily damaged.

Leaves may be torn or slightly shredded. Juicy or succulent foliage may be showing spotted dry spots. In almost all cases, these plants will recover. No need to panic; as new leaves replace old leaves the damage will eventually disappear.

RON VANDERHOFF is the nursery manager at Roger's Gardens, Corona del Mar.

Ask Ron

I loved last week's column about House Wrens. I've put up a wren house and can hardly wait. Now what do I need to do to attract these birds to my garden and their new home?

Allison, Newport Beach

You're on the way, Allison. As long as a wren house is in place, just stand back and wait. They'll come; the male first, then the female. For lots of birds in general, don't use harsh chemicals or systemic insecticides in your garden and keep a close eye on outdoor cats. Be cautious with traditional snail baits as well (these can be easily switched to much safer organic based alternatives). Wrens are likely already wandering through your garden in search of insects and suitable nesting locations. Just be patient.

ASK RON your toughest gardening questions, and the expert nursery staff at Roger's Gardens will come up with an answer. Please include your name, phone number and city, and limit queries to 30 words or fewer. E-mail stumpthegardener@rogersgardens.com, or write to Plant Talk at Roger's Gardens, 2301 San Joaquin Hills Road, Corona del Mar, CA 92625.