B. Rosie Lerner
Consumer Horticulturist







Question and Answer

Q. I have a cat that has been digging up the soil in my houseplants. I read in a magazine that mothballs can be used to keep rabbits out of the garden, so I'm wondering if I can use them on the top of the soil to discourage the cat.

A. In a nutshell, don't do it! While it is not uncommon to see mothballs recommended for repelling rodents and other animal pests, it is a dangerous and illegal practice. Mothballs, flakes and crystals are Environmental Protection Agency-registered insecticides, and they are not intended for use in the manner you suggest, in either the indoor or outdoor garden. In fact, they pose serious health risks to cats, dogs, and humans, and perhaps even to the plant you want to protect. In addition to the risk of ingestion, exposure to eyes and skin, and inhalation of the fumes can all lead to serious illness or injury. Further, it is illegal to recommend use of these products in a manner that is inconsistent with the pesticide label.

Mothballs have a high percentage of active ingredient, either naphthalene or paradichlorobenzene. These chemicals vaporize at fairly low temperatures, so they are particularly dangerous indoors at room temperature. Naphthalene is the more toxic of the two, but both have great potential to cause harm. These products should only be used according to label directions. Like all other pesticides, keep them out of reach of children and pets.

For more information on common misuse of moth-repellent products, see

http://www.ag.purdue.edu/entm/wildlifehotline/Pages/pesticides.aspx and http://npic.orst.edu/ingred/ptype/mothball/index.html.

Q. Some of the spring flowering bulbs that I planted this fall are sprouting and showing some foliage above the ground in early January. Is there anything I should do to protect them through the rest of winter?

A. Lots of gardeners are noticing their bulbs coming up, since the weather has been so mild, and there has not been much, if any, snow cover in many areas of the state. The most dramatic response is with early flowering bulbs, such as snowdrops, early tulips, daffodils and crocus. These plants may be showing a bit of their foliage above ground now, especially those that were planted near buildings or other warm, protected locations.

flower bulbs
Snowdrops, an early-spring flowering bulb, in Purdue's Horticulture Gardens. (image provided by Rosie Lerner)

These leaves will likely be nipped back once the temperatures drop back down below freezing again. In most cases, flower buds will remain protected inside the bulb below ground. If the warm temperatures continue for an extended period, the flower buds also may break out; some of the really early spring bulbs, such as snowdrops, may already have done so. Those blossoms that do show their heads will be nipped by a hard freeze once more normal temperatures prevail. However, the bulbs themselves will survive and come back next year, even if the flowers don't make it to spring this year.

There's not much a gardener can do to prevent nature from taking its course. Mulching over the plants now might smother them and would actually encourage growth by warming the soil further. And we have a lot more winter to get through before we know how the plants will fare.


Writer: B. Rosie Lerner
Editor: Olivia Maddox,