The Truth About Butterfly Bush

It was several decades ago when I was standing in front of a Meadow Lane mansion in Southampton consulting with the property’s gardener. We gazed upon planting after planting of butterfly bushes that were just covered, plastered with the southern migration of monarch butterflies. It was one of the most magnificent displays of nature that I’d seen. Then the gardener turned to me and said, “This is bad, very, very bad. These plants are so bad for the monarchs and yet the people out here keep on planting them.”

In mid-to-late-summer these plants are literally covered with monarch butterflies as they migrate south and seek fuel from the butterfly bush flowers for the long flight. And this is where the story gets twisted and contorted. It was widely thought that planting Buddleias would attract millions and millions of these butterflies that would feed on the pollen and nectar of the butterfly bush, which was then thought to provide an inferior source of these nutrients to the insects that needed to feed voraciously for their annual fall migration to Mexico. There were even statements made that this inferior pollen would affect the developing caterpillars that turned into the butterflies.

Not true! From years of study of the monarchs we know that these butterflies rarely lay eggs up here in their third generation (July into August) and never in their fourth generation, which is August to April, and they don’t lay their eggs on the butterfly bushes, only milkweed. So when these plants are in bloom the butterflies aren’t in a reproductive stage. Myth busted.

It was widely held that as a fuel source for the long flight down to Mexico, the butterfly bush, while a monarch magnet, was an inferior source of pollen and nectar for these butterflies and other insects. Again, not true. The monarchs do not feed on the pollen but on the highly concentrated nectar, which we now know is a high quality fuel for them as they make their southward trek. Another myth busted.

Remember also that Buddleia is not a native plant out here and may not be appropriate for those planning or who already have native plant gardens. However, there has been the assumption that Buddleia pollen is not equal to the pollen of our native plants, and while this seems to be true it may not be accurate to call Buddleia pollen “inferior.”

The other issues with the earlier Buddleias was that the species would copiously drop seed, which would result in seedlings showing up throughout the garden. As a result, in some states like Oregon, Buddleias are considered invasive and cannot be sold, and in New York it’s considered a “low” risk but still on the invasive watch list. However, just the species and not the cultivars. For this reason Spring Meadow Nursery, a licensee of the Proven Winners brand, only sells Buddleia cultivars in New York (such as the cultivars with “Miss” as part of their name like “Miss Molly”) and the five “Lo & Behold” cultivars, which are also sterile (or pollen free).

The plant unfortunately became known as a weedy plant, which accounts for its rise and fall among generations of gardeners. However, while this can still happen with the species, the more modern cultivars and hybrids rarely produce seed. Thus the newer introductions that are cultivars and hybrids can be quite attractive and nearly tame. Better yet, you can now find varieties growing only a few feet tall to as much as 6 to 8 feet tall.

Yes, Buddleias can get ratty looking if they don’t get some annual attention, but this work is easy and generally part of the spring cleanup that most gardeners and landscapers are familiar with.

Now there is yet another consideration with this plant if you want to bring it into your landscape. If you buy and use the new varieties that are hybrids and or cultivars, they may not produce any pollen or nectar that attracts pollinators including the ubiquitous monarch butterflies. On the other hand, the flowers on these plants can be so beautiful and magnificent when in full bloom that they can be very hard to resist. This is especially true for those gardens (and this may be most) that need to be in full bloom in late summer before Labor Day, when garden viewing out here reaches its peak.

There is some good news though thanks to the folks who do plant breeding. You can have Buddleias that will bloom as much as six weeks earlier than the older varieties. “Lo & Behold Blue Chip Jr.” at 3 feet tall can begin blooming in early summer and in flowering sequence several weeks later is “Pink Micro Chip” at 2 feet, then “Ruby Chip” at just over 2 feet, “Blue Chip” at 4 feet and finally in mid to late summer “Purple Haze,” which is just over 4 feet tall. These can then be followed up by the taller varieties like the “Miss” series, which bloom later and are slightly taller at about 5 feet tall.

Pruning Buddleias is critical if you want blooms and to keep the plants in great shape. Pruning is done in early spring just as the plants are about to break out. It’s important to remember that these plants only flower on new wood. If you forget to prune chances are you’ll get very few flowers and only on those branches that were damaged in the winter months from nature’s pruning.

You can cut the plants back to about a foot in late March or early April to force this new growth, but avoid the temptation to do this pruning in the fall or early winter as some foliage may remain (though tiny) which allows some photosynthesis to continue to feed the plants. Don’t be concerned about the amount of the older wood you take out because the more you remove the denser the plant that will result. You can find instructions on how to do this online or in a number of gardening books. A simple one can be found here: wikihow.com/Prune-Buddleia.

If you don’t prune your Buddleias each spring you will still end up with some flowers. However these flowers will only show up at the tips of damaged stems or at the tips of stems from last year’s growth. This is known as “second story” flowers and can be fairly sparse.

A long-neglected Buddleia, often found on older properties that have been neglected, can easily be rejuvenated though hard pruning in early spring, and as the season progresses you can deadhead the plants’ spent blooms, which can often lead to even more flowering into the fall.

In extremely cold winters the aboveground portions of the plant may die back, but I haven’t seen this in years. When it does happen, be patient and you’ll probably see new shoots emerging in May or early June.

Buddleias are not heavy feeders and should only need a light feeding with an organic granular fertilizer in April. The plants have few insect issues, and most will show up during the flowering period. This is a problem as you don’t want to inadvertently spray the pollinators that are present at the same time. Japanese beetles can be an issue, and these can be tapped off the foliage or flowers into soapy water or use spot treatments of neem oil on the beetles or a water based pyrethrin when the pollinators are not present.

Butterfly Bush can be found at most garden centers for $35 and up with the newer varieties being the most expensive, and the longer you wait the larger the plants will be — and more expensive. You can also order online from vendors like Bluestone and the White Flower Farm, but you need to do this early in the season as the better varieties seem to be sold out already. Check locally.

These are great shrubs. Generally easy to grow and care for, and once established they just need an annual pruning, light feeding then watch and enjoy as they color up the summer garden. They have the potential to make an August garden nothing short of spectacular. Need to know more about this plant? Take a look here: ngb.org/year-of-the-buddleia. Keep growing.