By: Liz Baessler
Large, brilliant, and long-blooming, butterfly bushes make for beautiful centerpieces in butterfly gardens and landscapes alike. When you’re anticipating innumerable long, pendulous, pollinator-attracting flowers, it can be a serious letdown if your butterfly bush will not bloom. Keep reading for reasons why there may be no flowers on a butterfly bush, as well as ways to get a butterfly bush to bloom.
There are a few reasons a butterfly bush will not bloom, most of them related to stress. One of the most common is improper watering. Butterfly bushes require plenty of water, particularly in the spring during their main period of growth. In the summer, they need steady watering during periods of drought. At the same time, the roots will rot very readily in standing water. Make sure your plant has adequate drainage to accommodate all that watering.
Butterfly bushes require at least partial and, preferably, full sun to bloom to their full potential. For the most part, they are very hardy to disease and pests, but they can sometimes fall victim to spider mites and nematodes.
In another vein, if you’ve planted your butterfly bush recently, it may still be suffering from transplant shock. Even if it was blooming when you planted it last year, it might still need a year to recover and put down new roots.
Perhaps the most common cause of a non-flowering butterfly bush is improper pruning. If left to its own devices, a butterfly bush can turn into an unruly thicket with sparse blossoms.
Prune your butterfly bush back in the autumn or early in the spring, before new growth starts. Cut at least some of the stems down to until only 3-4 inches (7-10 cm) remain above the soil. This will encourage new growth from the roots and more flowers.
If you live in an area that experiences very cold winters, your plant may die back to this state naturally and the resulting dead wood will have to be cut away.
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Read more about Butterfly Bush
In the late afternoon and early evening, when the summer sun is its most potent, the insects are in frenetic action. All over the garden, the tips of flowers launch into the air — if there were such thing as an insect air traffic controller, it would have lost its mind long ago. Bees, wasps, flies, moths, beetles and butterflies work to satiate their own hunger on nectar plants, while on others they gather pollen to feed their young miles away.
Above the native prairie plants — culver’s root, aster, boneset, coreopsis, milkweed, ironweed and American senna — the sound of wings can be heard 10 feet away. But over by the butterfly bush (Buddleja davidii ) , one lone tiger swallowtail works the blooms, like a tourist at a restaurant the locals never visit.
The Problems With Butterfly Bush
No one believes me, not even when I post videos online. The butterfly bush sees one-tenth, even one-twentieth of the action of almost any other native plant. Sure, an occasional butterfly or bumblebee, a sphinx moth, may fly by, but it's hardly anything to write home about. Even just as a nectar source, other nonnatives, like lavender and caryopteris, get far more insects — and as you know, insects are the base of the food chain for birds and us.
Here's the thing about butterfly bush. It has proven invasive on both U.S. coasts. Maybe not in small backyard gardens, but birds carry off the seed to the point that it's popping up in unmanaged fields and roadside areas.
A native of Asia, it has no checks and balances in the U.S., and as a larger wildlife-supporting plant, it just doesn't pass muster. I know we all plant butterfly bush to help insects, but the plant's name is simply as successful a marketing tactic as I've ever seen.
If our goal as gardeners is to appreciate and support diverse wildlife — which I hope it is — in conjunction with creating an aesthetically beautiful interpretation of nature, then we have to ask ourselves these questions: How many caterpillars do we see feeding on butterfly bush? How many species of insect do we see sipping nectar from it, compared to other plants in the garden?
Butterfly bush flowers limit the types of insects that can reach its nectar, but besides this the nectar and plant have no evolutionary history with native insects — they aren't adapted to each other, so they're like perfect strangers. Butterfly bush blooms for a long time and is an easy plant to grow, but there are other plants more beneficial to native butterflies and insects that go a lot further toward attracting and maintaining insect populations.
What to Plant Instead
The key to good garden design, and replacing butterfly bush, is succession gardening. This means always having something in bloom from spring through fall. When one key pollinator plant stops blooming, another turns on to take its place.
This way we can mimic the long bloom time of butterfly bush, which helps our garden aesthetically while benefiting insects. I'm going to run down a list of plants native to a large portion of the central and eastern U.S., but you should always confirm what's native to you. (Visit the websites for The Xerces Society, the Lady Bird Johnson Wildflower Center or Pollinator Partnership for helpful lists and guides.)
So here is the order I'd go with and what I'd use in areas with the medium to dry soil (clay to loam) and full sun conditions butterfly bush thrives in. And shoot, I've even tried to pick purple-blooming plants to mimic the most common bloom color of butterfly bush.
Generally hardy in nature, they do not take too much hard work and can get established in almost any type of well-drained soil. These plants have a fibrous root system, instead of a taproot, which means the roots get their nutrients from the upper layers of soil.
Where to plant them: Any sunny spot in your garden that remains reasonably dry throughout the year
Best time to plant: Spring, or fall (just before the frost)
When do they bloom: From summer to autumn
It is possible to start a butterfly bush from branch cuttings, but it is more common to get a small plant from nursery so you can be sure that it will not turn invasive. Propagating from seeds is often avoided for the same reason.
Three possible answers to this vexing mystery.
Like all decent individuals, you love butterflies. That’s why you filled your garden this spring with nectar-laden plants to attract these winged beauties – flowers like butterfly bush, butterfly weed, Joe-pye weed, lantana, pentas, zinnias, salvias, asters, blazing star, goldenrod, and summer phlox. But few of your invited guests ever showed up at the table. How come?
There are several possibilities, only one of which could possibly count as a moral lapse on your part. Let’s discuss.
It isn’t enough to provide nectar sources for adult butterflies. Without food for their caterpillars, there won’t be a next generation of adults. Caterpillars don’t drink nectar. They eat foliage from very specific plants, including trees, shrubs, herbs, vines, and common weeds. For example, monarch butterfly caterpillars feed only on plants in the milkweed family, such as common milkweed (Asclepias syriaca) and butterfly weed (Asclepias tuberosa). Tiger swallowtail larvae eat leaves of black cherry (Prunus serotina), tulip poplar (Liriodendron tulipifera), and maples (Acer sp.). Those of black swallowtails chow down on parsley, dill, and carrot. Spicebush swallowtails gobble spicebush (Lindera benzoin) and sassafras (Sassafras albidum). Zebra swallowtails munch on pawpaw (Asimina triloba). Fritillary larvae dine on violets and passion vine (Passiflora sp.). Painted ladies hold out for hollyhock, mallow, and thistle. Buckeyes snack on lawn weeds like plantain and cudweed.
Thus, if your yard and those around you look like a manicured fairway at Augusta National golf course, it’s safe to say butterfly larvae will be scarce. No kids mean no grownups. The more native plants growing in the landscape around you, the more butterflies you’ll see.
Not all butterflies hang around where they were born. Some migrate as the seasons progress to take advantage of flowers just opening up and also favorable weather. Monarch butterflies that fly in the millions from the U.S. heartland to southwestern Mexico each year are the most famous migrators. (For everything you could ever want to know about this phenomenon, read this book: The Monarch – Saving Our Most Beloved Butterfly by my friend, Kylee Baumle.) However, plenty of others migrate as well, including the Gulf fritillary, red admiral, cloudless sulfur, buckeye, and painted lady. Thus, if the butterfly show has been meager so far, be patient and they’ll hopefully appear.
Patience won’t do much good if you kill them when they arrive. I’m appalled at how many people fog their yards with insecticide every summer to kill mosquitoes. These long-lasting, indiscriminate pesticides kill many more beneficial bugs (and pollinators) than annoying mosquitoes. If you fog your yard, say goodbye to butterflies, moths, fireflies, honeybees, praying mantises, and ladybugs. Because the fog goes any way the wind blows, you’ll likely turn your neighbor’s yard into a dead-zone too. Grumpy says handle mosquitoes as we always have. Cover exposed skin or apply insect repellent. The world isn’t all about you.
The butterfly bush (Buddleia davidii) has long been a staple of the southern garden. In recent years, however, its habit of prolific re-seeding has come under attack. After a year or two in the landscape, the home gardener is inundated by seedlings popping up all over the landscape and into neighboring fields and woodland areas. Being a fast grower, the butterfly bush can quickly become established in wild areas, choking out native plants. While our local climate seems to keep the plant in check, home gardeners often complain about the problem of numerous seedlings.
The butterfly bush is a draw to butterflies who come to feed on the nectar that is produced. But because of its invasive qualities, almost half of U.S. states have banned the sale and planting of Buddleia (NC is not one of them). Because of its fast growth habit, it can be a challenge to maintain and yearly pruning is needed to keep it to a manageable size.
But, there are some “fixes” for this problem shrub for folks who don’t want to give up their butterfly-attracting plants. Frequent dead-heading before seeds are dispersed will cut down on seedling production as well as encourage more flowering. There have been introductions of sterile varieties of buddleia or those that have very low seed viability, resulting in few pop-up seedlings. These sterile introductions are also much smaller, making maintenance much easier.
If you don’t want to give up on having a butterfly bush in your garden, there are plenty of new introductions that will meet your specific needs. The Flutterby series is one of the sterile, smaller-growing choices as well as the Lo & Behold series. They offer many colors and sizes for our Burke County gardens.