HAWAI'I GARDENS
More plants may help control those wild weeds

By Heidi Bornhorst

Dear Heidi, how do I control weeds without using harmful chemicals? We have keiki who love to roll around on the lawn and have cherished geckos.

Dear Maile: If you have weeds, you don't have enough plants!

This is a basic landscape maintenance concept. Plant lots of vigorous plants and choke out the weeds. You can also "shade them out" to keep them from sprouting in the first place.

There are other, chemical-free ways to control and suppress weeds.

• Use mulch. By mulching around your plants, you can suppress and smother the weeds, insulate and cool the soil, and save on watering. But keep the mulch away from the trunks and stems of plants.
• Water your plants roots directly and don't water the weeds. Watering by hand is the best way to accomplish this, and some drip-irrigation systems also work this way.
• Pull weeds while they're young. Pull the weeds before they flower and set seed. Just a little weeding every day will help. Squatting down and pulling weeds also keeps you flexible and strengthens your bones (no need go gym!).
• Don't overcultivate the soil. Let sleeping weed seeds lie. Every time you till or hoe the soil, new weed seeds are dredged up from the lower soil layers.
• Plant hedges. Hedges make for good neighbors. If your neighbors have a lot of weeds, hedges will help keep the weed seeds from blowing in. Hedges also are great for screening ugly views, muffling noise and keeping windblown dust out of your yard.
• Use cover crops. A cover crop is something you grow and then plow back into the soil. It covers up spaces where weeds could get started, some fix nitrogen and enrich your soil. Nanea is an excellent cover crop: It has pretty yellow flowers, it's vigorous, it easily reseeds and it has great nitrogen nodules on the roots. Soybeans and Chinese peas work well as edibles that you plow under after harvest.
• Don't allow hitchhikers! Conscientious hikers clean their boots of weed seeds before hiking into clean areas. The same holds true in gardens. Wash off those muddy golf shoes and hiking boots. Some people keep any foreign soil, dirt and oils out of their garden by using a pair of zoris only for the garden.

Plant sale of the season on July 13

At the Lyon Arboretum Summer Plant Sale, 9 a.m. to 2 p.m. July 13 at the Blaisdell Exhibition Hall, not only can you find wonderful plants and trees, you can get gardening advice and browse for gifts as well.

More than 35 nurseries participate in this prime plant sale, offering thousands of plants: native Hawaiian plants, heliconias, gingers, fruit trees, water plants, herbs, ferns, ti, orchids, anthuriums, cacti and succulents, bonsai, bromeliads, palms, day lilies.

Gardening experts will offer their advice. Crafts, lei, jams and jellies, books, T-shirts and more will be on sale. There will be activities for the keiki, too. Proceeds help to support many programs at the arboretum. Admission is free. 988-0464 or 988-0472.

Ideal time to grow dwarf crepe myrtle

Dwarf crepe myrtle is blooming in many home gardens and planned developments. You'll know them by their five-petal, crepe-paper-like blossoms of pink, lavender and purple.

The miniature varieties are hedges or small trees well-suited to our small gardens. They are easy to grow and are available at landscape nurseries.

Heidi Bornhorst is director of Honolulu's botanical gardens. Reach her at islandlife@honoluluadvertiser.com or The Honolulu Advertiser, P.O. Box 3110, Honolulu, HI 96802. Letters submitted to The Advertiser may be published or distributed in print, electronic or other forms.