What bug is eating my perennial hibiscus?
Those skeletonized leaves are a sure sign that you’ve got Japanese beetles eating your plants. Unless the infestation is extremely bad, they usually won’t kill your hibiscus but they sure can reduce its vigor and flowering. There are several commercially available pesticides that can kill them. I have also heard that Four O’Clocks (Mirabilis jalapa) are quite tempting to Japanese beetles but are also poisonous to them. I’m going to be planting them around all of my Japanese beetle-susceptible plants to see how well they work.
How to kill carpetweed
We’ve just purchased a home with carpetweed covering large swaths of pachysandra (about 1/4 acre of carpetweed). Beyond pulling, are there pre- or post-emergent herbicides that kill weeds without harming pachysandra? And even if it’s too late for this summer, maybe some suggestions for future seasons?
I’m assuming you mean the noxious weed Mollugo verticillata and not the groundcover Ajuga, which often goes by the same name. The pesky carpetweed is an annual weed so it can be controlled quite well by using a pre-emergent herbicide. Pre-emergent herbicides kill newly germinating seed so they will not harm your pachysandra. Carpetweed seeds germinate relatively late in the season so you will want to time your application a bit later than a typical weed and feed lawn application. There will be a large store of seed in the soil so it will likely take a few years to eradicate it all.
Why are my miniature butterfly bushes perishing?
I had eight miniature butterfly bushes now in their second summer. They were all doing great until I noticed two looked wilted. Two died. Then the two next to them died too. Should I bother replacing them next spring or go with something different? I am not an expert gardener but love plants and try to take good care of them. This has been so distressing! Any ideas would be greatly appreciated.
I do hope this doesn’t sour you on gardening. The best gardeners are the ones who’ve killed the most plants. Butterfly bush really needs quite good drainage and I’ve noticed the miniatures are even more susceptible to wet feet than the larger ones. This makes them excellent in containers and on slopes but they can be tough in our clay soils. This exceptionally wet summer certainly did not help your plants.
Mark Weathington is the director of the JC Raulston Arboretum at N.C. State University in Raleigh. Info: jcra.ncsu.edu. Please send your gardening questions to: firstname.lastname@example.org. To have your answer published, you must include your full name and the city where you garden.
Common name: White Mallow
Botanical name: Hibiscus coccineus f. albus
Family: Mallow (Malvaceae)
Category: Dieback shrub
Primary uses: Perennial borders, bog gardens
Dimensions: 6 to 8 feet tall by 4 to 6 feet wide
Culture: Sun to light shade. This form of the typically red flowered native hibiscus grows naturally in wet soils, but is equally at home in average garden soil. The foliage is somewhat less susceptible to Japanese beetles than many other mallows. Cut back the stems in late winter before the new growth emerges.
Bloom time: Summer
General attributes: Finely dissected leaves cover stems which erupt from the ground in spring and quickly reach up to 8 feet tall. In mid to late summer, pure white flowers 6 inches or more across light up the garden. The winter stems turn white and provide color and substance even when dormant.