Like many gardeners, I grow milkweed because I think it is pretty but mainly for the butterflies. Butterflies of many kinds enjoy sipping from its flowers, but butterflies like the Monarch and the Queen are completely dependent upon it for the nurturing of their larvae.
As we know, the Monarch in particular has been declining in recent years and one of the reasons has been the destruction of milkweed plants by industrial and agricultural development along its migration route across the continent.
Throughout the year, the Monarchs flit through my garden and many of them lay their eggs on the milkweed plants there.
And soon I find their caterpillars happily munching their way through the leaves of the plants. A heavy crop of caterpillars can completely strip the leaves from a plant in a few days. Through our long growing season, an individual plant may regrow its leaves several times.
Nearing the end of the season, the plants develop their feathery seeds which will be spread by the wind if the gardener doesn't remove them. The result can be "volunteer" milkweed sprouts in unlikely, unexpected places around the garden.
Also, as the season advances, the plants are host to many different insects like the milkweed bug in the above picture. As the plant declines, they signal their vulnerability to the insect world and become prey to more sinister leaf chompers and suckers.
The most destructive of these, from my point of view, are the aphids. A crop of these can really uglify a plant in short order.
I would prune off the affected limbs along with their squatters except for one thing: Where there are aphids, there are ladybugs on the job.
Ladybugs love aphids! Over a few days, they will completely scour a plant of them. Then will be the time to cut the plant back and let it regenerate.
Even more voracious devourers of the aphids than the adult ladybugs are their larvae, like this little guy. It takes a lot of aphids to transform this into an adult ladybug and that's good news for the gardener.
Also aiding in the fight against bad bugs are spiders like this tiny jumping spider.
By this time of year, the milkweed plants that were so pristine and pretty in the spring have become an eyesore in the garden. But they are still providing important habitat and food for many insects, arthropods, amphibians, and reptiles. Gardeners who understand this can easily tolerate the ugliness for a while. When the aphids are gone, the plants can be cut back and, at least here in zone 9a, they will regenerate and probably be in flower again before the end of the year.
Ready to sustain and nurture more generations of Monarchs and Queens.