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. This beetle is commonly called the "ladybug," also referred to as the "ladybird beetle" or "lady beetle."
There is more than one type of ladybug. Hippodamia convergens is one that is native to North America. The Asian ladybug (Harmonia axyridis) is also commonly found in North America, but it is an introduced species. Native-plant enthusiasts in North America, preferring to keep their beneficial insects native, too, generally want to attract Hippodamia convergens to their yards; it is with this species that we are concerned here. But other kinds of ladybugs include:
- Coccinella septempunctata: The seven-spotted ladybug is native to Eurasia. It is best known for eating aphids and scale insects.
- Coleomegilla maculata: The pink spotted ladybug is so called because the background on which its spots appear can be pink or red. Native to North America, the shape of this beetle is oval. It is valued for eating aphids and mites.
Do not assume that all ladybugs are beneficial. The Mexican bean beetle (Epilachna varivestis) is a kind of ladybug that eats plants, not pests. If you live in North America, stick with Hippodamia convergens to be on the safe side.
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 4 to 6 inches high, with a spread of 6 to 9 inches. Sweet alyssum is a sun plant that likes good drainage but is easy to grow. The white-flowered kinds are most popular.
Besides being a butterfly magnet, butterfly weed (Asclepias tuberosa) attracts ladybugs with its brilliant orange flowers. Grow this perennial in full sunlight. It stands 1 to 2.5 feet tall, with a spread of 1 to 1.5 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 6 to 10 inches high and 4 to 10 inches wide. Cilantro likes a rich soil with good drainage and slightly acidic 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 to 18 inches tall and 9 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 2 to 4 feet tall, with a spread of 1 to 1.5 feet. This yellow-flowered perennial likes full to partial sun and 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. Note that in certain states it is considered a noxious weed and should not be grown in conditions where it could spread.
Tickseed (Coreopsis) is a perennial for zones 4 to 9. Grow it in full sun to partial shade and in a soil that drains well. It measures 10 to 18 inches tall and 12 to 24 inches wide. Flowers come in yellow (such as the popular C. verticillata 'Moonbeam'), orange, pink, and red; some cultivars are bi-colored.
Yarrow (Achillea millefolium) grows in zones 3 to 8. It attains a height of 3 feet and a width of 2 feet. An aromatic perennial, it is most valued for its airy, fern-like foliage and flat-top flower heads. Cultivars come in colors (red, yellow, etc.) other than the standard white you see growing along roadsides. Like tansy, yarrow is not fussy to grow: Full sun and a well-drained soil are best, but it will tolerate clay soil better than many plants and is drought-tolerant once established.
Mexican Bean Beetle. University of Florida
Sooty Mold. University of California Agriculture & Natural Resources
Ladybugs. University of Kentucky College of Agriculture, Food and Environment
Tanacetum Vulgare. Missouri Botanical Garden
Yarrow. University of Florida Institute of Food and Agricultural Sciences Extension