Beginning gardeners may be surprised to learn that not all beetles are pests. There is a type of beetle that is actually beneficial to the garden because it eats certain bugs that are pests: the ladybug, also referred to as the "ladybird beetle" or "lady beetle." There is more than one type of ladybug, but the one we'll be focusing on is Hippodamia convergens. It is native to North America, and gardeners who grow native plants often prefer to keep their beneficial insects, native, too.
If you find plants in your yard covered with sooty mold and/or ants, the true culprit may be one of the sucking insect pests, such as aphids. Detecting and fighting these pests can cause you a lot of extra landscape maintenance. Ladybugs can help you with this work because they eat such pests. Luckily, there are plants that you can grow to attract these beneficial insects to your garden.
Garden Pests That Ladybugs Eat
You may be used to fighting beetles such as June bugs (Phyllophaga longispina), Colorado potato beetles (Leptinotarsa decemlineata), and Japanese beetles (Popillia japonica). Hippodamia convergens offers a welcome change of pace. Rather than eating your plants, these ladybugs eat some of the pests that do eat your plants. As a bonus, even the larvae of ladybugs eat garden pests. Just one ladybug can eat 5,000 aphids in its lifetime.
Pests that these ladybugs eat (for which the average gardener will be grateful) include:
- Asparagus beetles (Crioceris asparagi; ladybugs eat their eggs and/or larvae)
- Green peach or "peach-potato" aphids (Myzus persicae)
- Potato psyllids (Bactericera cockerell)
- Spider mites (Tetranychus spp.)
When to Start Growing Ladybug Plants, When You'll See Results
Some of the plants that you will be growing to attract ladybugs are annuals or biennials, while others are perennials. Gardeners generally buy the latter already-started from a garden center. Annuals and biennials can either be started from seed or bought already-started from a garden center. Either way, the safest time to put them in the ground is in late spring, once all danger of frost has passed.
Since it is the pollen and nectar from the flowers of these plants that ladybugs are drawn to (they eat it), you will see results during the bloom times for these plants. These bloom times vary. For example:
- If you buy an already-started June-bloomer from a garden center in June, it may be in bloom when you buy it, so it can begin attracting beneficial insects immediately.
- By contrast, a perennial such as tansy will not begin blooming in the North until mid-summer.
- If you start a biennial from seed, it will not bloom until its second year.
Plants That Attract Ladybugs
The complete list of plants effective for drawing ladybugs would be too long to provide. The following list is designed to offer a mix of edible plants and ornamental specimens:
The filler, sweet alyssum (Lobularia maritima), is commonly treated as an annual in zones 5 to 9. This short, spreading plant grows four to six inches high, with a spread of six to nine inches. Sweet alyssum is a sun plant that likes good drainage but is easy to grow.
Besides being a butterfly magnet, butterfly weed (Asclepias tuberosa) attracts ladybugs. Grow this perennial in full sunlight. It stands one to two and a half feet tall, with a spread of one to one and a half feet. This is another easy plant to grow, surviving even in poor soils, as long as they drain well. It performs best in zones 3 to 9.
Cilantro (Coriandrum sativum) is an annual herb and especially useful in Mexican recipes. Grow it in partial shade. It grows six to 10 inches high and four to 10 inches wide. Cilantro likes a rich soil with good drainage and a neutral soil pH.
Anethum graveolens is a tall (18 to 40 inches), skinny plant that needs full sun. Because it has a long taproot, be sure to provide this annual herb with a loose, well-drained soil that will not stop the taproot from anchoring deep below the ground surface. Dill is for more than just pickles; it adds great flavor to fish dishes and more.
Curly-leaved parsley (Petroselinum crispum) is another culinary herb, but this one is a biennial for zones 2 to 11. It becomes 12 to18 inches and nine to 12 inches wide. Not fussy about sunlight requirements (anything from full sun to partial shade will do), parsley does want a rich, evenly moist, well-drained soil.
Tansy (Tanacetum vulgare) can be grown in zones 3 to 9. It stands two to four feet tall, with a spread of one to one and a half feet. This perennial likes full to partial sun and a well-drained, fertile soil. It is not fussy at all about soil pH, making it a highly adaptable plant. Once an important medicinal herb, it is treated now more as an ornamental.