Ask the ISU Extension Garden Experts: ZZ Plants, Butterfly Houses and Pine Wilt

I recently purchased a ZZ plant. How do I care for it?

The ZZ plant (Zamioculcas zamiifolia) is a tough, easy to grow houseplant. It tolerates low levels of light, prolonged dry periods and neglect. Plants have few insect or disease problems. Zamioculcas zamiifolia is also known as aroid palm, eternity plant and fat boy.

The ZZ plant performs best in bright, indirect light. However, it will tolerate very low levels of light. Direct, afternoon sun actually may damage the plant's foliage. The plant prefers to be kept on the dry side. When watering, water plants thoroughly. Some water should flow out the bottom of the pot. Discard any excess water. Allow the potting soil to dry nicely before watering again. In most cases, a thorough watering every seven to 14 days is usually fine.

Problems can develop if the plant is watered too frequently and the potting soil is constantly wet. In spring and summer, fertilize once or twice a month with a dilute fertilizer solution.

The ZZ plant grows rather slowly. When it grows, it tends to grow in spurts. Plants are propagated by leaf cuttings and division. The ZZ plant is poisonous to humans and pets if ingested.

Do butterflies actually use butterfly houses?

Butterfly houses are also known as butterfly roosts and hibernation boxes. Supporters claim these birdhouse-sized structures encourage butterflies to stay in your garden by providing necessary shelter.

Butterfly houses are attractive additions to the home garden. However, several studies have shown that the boxes are virtually never used by butterflies. (Spiders, wasps and mice are the most common occupants of butterfly houses.) The few butterflies that do remain for the winter appear to find sufficient natural hiding places under dead leaves, twigs and wood piles, where they hang upside down with their wings folded together.

The best encouragement for butterflies is to diversify your landscape. Plant a wide variety of flowers and plants that are attractive to butterflies and will feed the hungry caterpillars. Also, reduce insecticide use as much as possible.

What causes pine wilt?

Pine wilt is a common disease that causes browning and death of pines, especially Scotch pines. Austrian, mugo, red, jack and white pine also may be affected, but less commonly than Scotch pines. Affected trees turn brown and die within a few months.

Pine wilt is caused by the pinewood nematode, a microscopic worm. The nematodes clog the water-conducting vessels of the pine tree, causing the tree to wilt and die. It spreads from tree to tree by pine sawyer beetles. Infected, dying trees are often attacked by secondary bark beetles, which leave small holes in the trunk and carry a fungus that causes blue staining of the wood, often visible as blue radial wedges when the trunk is cut in cross-section.

Unfortunately, there is no cure for pine wilt. Dying trees should be cut down and destroyed.

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