Episode 57 – To Prune or Not to Prune? Cleaning-up the Garden in Fall

Ground Breaking Banter - Rick

On this week's show, we're talking about fall clean-up and the always perplexing question of what to cut back and what not to cut back. In general, herbaceous perennials, which come back from the ground, can be cut back, whereas shrubs, which emerge on the branches that persist through winter, should not. But when in doubt, just don't prune! Besides, many people nowadays espouse a "leave the leaves" (and stems!) approach, which provides habitat, protection, and food for overwinter insects, birds, and other wildlife. Hear the whole conversation on your favorite podcast platform or at the YouTube link above.

Caryopteris is also known as bluebeard and blue mist spirea, and though it is actually a shrub with stems that are made of true wood, many people think of it as a perennial, and that leads to confusion on when – and if – it should be cut back. So on this show that’s dedicated to cutting things back and knowing the difference, I thought I’d tackle a plant that has often caused confusion.

But first, let’s paint the picture of Beyond Midnight caryopteris. With two common names that include “blue,” it’s probably not surprising that the flowers are, indeed, blue. And I’d say the overall impression of the plant is a true blue because Beyond Midnight has much darker foliage than your typical caryopteris. It’s a unique silvery-green color that makes a beautiful contrast with the purple-blue flowers. But what’s really special about Beyond Midnight, and caryopteris in general, is that it blooms in fall, bringing unexpected color and interest to the landscape. It’s also a pollinator magnet. A former colleague of mine used to call it “the bumblebee motel” because that is what it’s like – just a pulsing, buzzing mass of life in bloom. Especially since it’s super floriferous. Another feature is that after the whiskered (hence the name “bluebeard”) flowers fall, the little bract they leave behind turns a dusty blue color. It’s really an interesting transformation.

Caryopteris is best treated like butterfly bush – it has similar growing needs and grows in a similar manner. So if you have butterfly bush and have been successful with it, caryopteris is a natural addition to your garden. If you’re new to it, this is a plant that you should cut back in spring. Like butterfly bush, it can experience winter dieback in the colder ends of its range (USDA zones 5-6 – it’s hardy in zones 5-9), so is best left whole for winter, which helps to protect the buds. Some caryopteris will spread by seed, so if this is an issue, just prune off the spent flowers in fall and save any major pruning for spring.

If you’d like to add Beyond Midnight caryopteris – or any of the 320+ Proven Winners ColorChoice Shrubs – to your garden or landscape, you’ll find a list of local retailers here

Gardening Mail Bag - Stacey

One of the tricky things about roses of Sharon is that the flower buds and seed pods look similar to the untrained eye, so very often, what someone thinks should be a flower actually was one already. The easiest way to tell is to use your garden pruners to cut one in half. If it reveals something that looks a bit like a cross-section of okra, with a lot of round, white seeds inside, it’s a seed pod. If you’re seeing something else, it may be a flower bud that’s not opening, particularly if it’s earlier in the season than September-October. 

Roses of Sharon under extreme stress might not bloom, but in this case, the stress would also be manifesting in unhealthy looking foliage, poor growth, etc. Another possibility is something known as a hibiscus midge, a tiny fly that burrows into the developing flower bud. You can test for the presence of these in summer by placing some buds (or what you suspect are buds) in a plastic bag and putting it in a warm spot for a few days. If it is the midge, the tiny larvae will be visible in the bag. This is an unusual case for roses of Sharon, though.

The fact that this seems to coincide with recent tornado damage suggests that there is additional damage to the tree that you might not be seeing. It’s not normal for pine sap to flow very strongly at this point, so it’s probably due to injury. Another possibility is a bark beetle. There are a number of different types that can take up residence in pines, but in severe infestations, the pine will increase sap flow in an effort to unseat them from their chosen home. We recommend that you get a pair of binoculars and search the tree to find the source(s) of the sap, and look for either cracks, splits, or other breakage nearby, or the tell-tale holes and sawdust-like substance known as frass.

Hydrangeas are susceptible to a number of leaf spots, especially in years with high spring rainfall, high humidity, and in scenarios where the foliage is frequently wetted by irrigation. Though they are unsightly, they are not harmful to the overall health of the plant. It’s important to understand that fungal leaf spots are on the plant, not in the plant, so once the foliage drops in fall, the disease goes with it. However, the fungal spores do spend winter on the leaves, waiting to reinfect the plant the next spring if conditions allow. As such, we do recommend carefully removing and discarding all the foliage when it drops – this will go a long way toward minimizing leaf spot in the future, though in years where conditions are very favorable to its development, you may still see it from time to time. 

Do you have a question for us? We’re happy to help! E-mail us or use the contact tab above. Due to high volume, we may not get to your question, so if you need an answer quickly, please reach out via the Proven Winners website.

Branching News - Rick