Lauterbach: They're bad, and they might be coming to your yard

Special to the Idaho StatesmanJune 7, 2013 

0817 local Japanese beetle.JPG

Seen this guy? Beware.

Japanese beetles are set to emerge this month, so be on the lookout for them. We've been lucky to be free of them until now, but a few were trapped in Downtown and West Boise last year. Some may have escaped the traps, and begun to lay eggs.

They burrow into the soil and lay about five tiny eggs, then emerge to feed, skeletonizing leaves of our valued ornamentals for a day or two before returning to the soil to lay more eggs.

Each female may lay 40 to 60 eggs by the middle of August, when that activity ceases.

Larvae are white grubs that feed on plant roots, especially grassy roots. They can kill large patches of lawn.

These beetles, emerged from pupas in plant containers here, were shipped from nurseries in other parts of the country.

If you see small beetles, nearly a half-inch long, with greenish heads and coppery wings, capture them and put them into a container and mail or take them to Mike Cooper or Jodie Ellis at the Idaho Dept. of Agriculture, 2230 Old Penitentiary Road, Boise, ID 83712, with a note telling what part of the Valley you found it, time and date, and what it was feeding on. Cooper asks that you not "smush" the critter so they can get a definite identification.

These beetles are active for only a couple of months above ground, feeding voraciously on roses and over 400 other fruiting and ornamental plants.


Some of our yuccas are coming into bloom now, a shaft of fragile lovely blossoms atop a cluster of dagger-like leaves. If you ever planted a yucca, you may have waited years for them to break into blossom.

They are similarly slow to germinate from seed.

If you plant yucca seeds, you should plant in fall, outdoors, so the seeds will be frozen and thawed (stratified) to spark germination. Even so, it may be a year or more before they do germinate.

Even then, your plant parenting isn't done. You should keep it in containers (ever larger ones) for two years in a sheltered environment. Only then should you plant it outdoors.

Yuccas are propagated by seed and by runner, setting offsets next to themselves. Starting it from seed is complicated for a plant that grows wild in the American West.

In its favor, yucca looks interesting year-round, and has practical uses. Its root is used for soap, or at least was so used by Native Americans to wash their hair. Its fibers were used for sewing thread, spiky leaves used for weaving baskets and even sandals.

Julian Martinez, husband of the great San Ildefonso potter, Maria Martinez, decorated her pots using a split piece of a yucca blade for a fine paintbrush.

As we travel through the West we tend to overlook the common yuccas and sagebrush, but a single specimen in a home landscape provides beauty and interest. It's a fine selection for a xeric landscape, requiring little water once established.


Do you have old fabric shopping bags? Get or sew new ones, and put those old bags to work holding plants. They make fine planting containers, letting moisture seep through the fabric. Some mail order companies are selling some huge cloth bags for folks to grow tomatoes or potatoes in.

Send garden questions to or Gardening, The Statesman, P.O. Box 40, Boise, ID 83707.

Idaho Statesman is pleased to provide this opportunity to share information, experiences and observations about what's in the news. Some of the comments may be reprinted elsewhere in the site or in the newspaper. We encourage lively, open debate on the issues of the day, and ask that you refrain from profanity, hate speech, personal comments and remarks that are off point. Thank you for taking the time to offer your thoughts.

Commenting FAQs | Terms of Service