Skip to content

Joy Says: “Grow Green!”

For gardeners, going green can take many forms: being careful about pesticides you use on your plants to keep them healthy and pest-free, and being mindful of invasive species that can take over our native plants and change the ecology of the region.

Japanese KnotweedEverything is green-green-green these days. We’re all trying to be friendlier to the environment, but much damage has already been done. There are reports every day about the risks of pesticides or groundwater contamination. I’m grateful we live in an area where most of us try to practice being green.

For gardeners, going green can take many forms: being careful about pesticides you use on your plants to keep them healthy and pest-free, and being mindful of invasive species that can take over our native plants and change the ecology of the region.

Crawly Pests

There are natural methods you can use to keep bugs and slugs from feeding on your plants or harming your fruits and vegetables. Here are some specific green ways to keep your garden from being munched:

  • Crush up clean eggshells and place them around plants. Slugs will stay away from the shells’ sharp edges or risk being cut.
  • Earwigs seem to love sandier soil and damp mulch, so look for them there. They can munch on plants quickly. Garlic oil sprays keep them at bay.
  • Keep your cat happy at the same time you fend off aphids, beetles, squash bugs, and ants: Plant catnip! It also repels mice.
  • Adding flowers to your vegetable bed might seem strange, but flowers often stop pests and plant diseases. The white flowering chrysanthemums repel Japanese beetles. Geraniums keep out cabbage worms, Japanese beetles, and beet leafhoppers. Nasturtium deters both bugs and beetles. Pretty petunias keep out asparagus beetle, leafhoppers, aphids, tomato worms, Mexican beetles, and general pests; use the leaves in a tea for a potent bug spray. Planting sunflowers will attract aphids and ants to them instead of your other plants, and sunflowers are tough enough to take it. Sunflowers attract hummingbirds, which eat whiteflies—and you’ll have sunflowers seeds to attract birds later on!
  • Garlic is a famous fungicide because it accumulates sulfur. Garlic it is taken up by neighboring plants through their pores, and if you make garlic tea and drench the soil, it’s also taken up by the plant roots. Garlic is offensive to moths, beetles, root maggots, snails, and carrot root fly. Garlic sprays (a low concentration, about 5%) repel and kill whiteflies, aphids, and fungus gnats.
  • Root plants can lure some pests away from your other crops. Radishes keep leafminers away from spinach, and even though those bugs will eat your radish leaves, the radish roots remain healthy!
  • Ladybugs are usually welcome because they eat aphids and other small pests. However, if you’re being overrun by them—especially if they’re making their way inside—try  putting bay leaves around plants or on windowsills indoors. Sprinkle dried bay leaves in your garden as natural insecticide dust; many bugs don’t like the strong scent.
  • Homemade sauerkraut is a Door County specialty! Plant clover between your cabbage plants to discourage aphids and cabbageworm. This kind of “companion planting” is a natural way of pest management and plants can help each other; nature integrates a diversity of plants, insects, animals, and other organisms into every ecosystem so there is no waste. You can use certain plants as a border, backdrop, or interplanting in flower or vegetable beds. For example, radishes are a deterrent against cucumber beetles. Intercropping onions and leeks with carrots will keep carrot and onion flies from reaching your carrot crop, and onions planted near strawberries keep strawberries disease free. Rosemary is a wonderful herb; interplant it to keep away cabbage moths, bean beetles, and carrot flies. In fact, it seems that any herb you’d use in turkey stuffing seems to work against pests—try planting thyme and sage as well.

Walking Pests

Garlic MustardDeer and rabbits—those are our main adversaries in the garden!

  • Most animals have a keen sense of smell and stay away from odors they dislike or that seem threatening. For instance, human or pet hair hung on plants will keep deer away (bunch it up in a section of pantyhose and tie the ends); if we have a rainy spell, you’ll have to replace the bundles.
  • Clove oil is an unpleasant smell to many animals. You can buy it at a health food store Mix some up with water and spritz on new fruit like apples. Deer won’t even take a bite, and clove oil won’t hurt the fruit.
  • The smell of garlic will keep away deer. Some use a concentrated spray (see above), but others swear by planting time-released garlic capsules at the bases of fruit trees. It’s safe and worth a try…you can ingest the leftover capsules yourself if the method doesn’t work (garlic is great for your health!).
  • Marigolds are known for keeping bunnies away, but you have to choose a variety with the strongest scent. We can lead you to them in the nursery. (Marigolds also repel whitefly and some other flying pests.) Plant as a barrier around tomatoes, cabbage, cucumbers, and under fruit trees, and potted marigolds are a good idea because they can be moved from spot to spot in your garden.

If your garden is overrun and you must resort to pesticides or chemical deterrents for animals, consult us for the best ones. One error most gardeners make is using too much or in too concentrated a solution. This not only harms the ecology but can ruin your plants, too. Think responsibly about what we put in the garden! In Door County, water quickly runs through the dolomite rock, and all those chemicals reach our drinking supply (for those with wells) and the bay and lake. A good source we often give people is the University of Wisconsin’s horticulture website: There’s a wealth of information on all aspects of gardening.

Invasive Species

Purple Loostrife

Not only do we have to watch the water for Asian carp, we have to control invasive species such as phragmites reeds that takes over our shorelines and wetlands, and the green Cladophora algae on our beaches. Your garden has similar problems. The plants look innocent enough—they’re often pretty—but they can take over a garden or plot of land and decreasing out native biodiversity. The Door County Invasive Species Team was formed in 2001, and the group works with nearly 30 businesses or private individuals in Door County to help control plants such as invasive purple loosestrife, white-flowered garlic mustard, and Japanese knotweed.

Invasive species also degrade habitats that birds and butterflies depend upon for reproductive success. If you want to grow green, it’s important to recognize these “volunteers” in your garden. Look at the Invasive Species Team website,, and you can educate yourself on identifying invasive species, reporting an invasive that may become a problem, and learning how to control them on your own property. With some species, such as garlic mustard, pulling out the entire plant will stop its spread; however, the seeds of a garlic mustard can stay viable in the soil for up to five years. It’s best to bring a sample in to us or send it to UW’s horticulture department if you’re unsure of what you’ve got. A good guideline: If you don’t know it, don’t grow it!