Pruning hydrangeas is a spring gardening chore you can do now, as weather permits, so long as you know which type of hydrangea you have growing in your yard. And the key to knowing when and how to prune also depends on when your hydrangea blooms.
Late spring and early summer bloomers have branches that overwinter. Those bloom on the previous year's growth, or "old wood." This goes for hydrangea types like blue or pink hydrangea, mophead, lacecap, oakleaf or climbing hydrangea. Those should be pruned right after the hydrangea is done blooming, ideally right after its blossoms fade.
More from Vermont Public: Prune hydrangea with confidence using these handy tips
Late summer and early fall bloomers can be pruned now to remove dead, dried stems and flowers and to reshape the bush.
Flowering bushes like panicle hydrangea, for instance, bloom on new wood and stems, and these kinds can be trimmed back now so they’ll grow even more.
When pruning now, you needn’t hold back. Removing half of the bush and branches isn't too severe. Cut the hydrangea back to a preferred height to encourage new growth and plenty of flowers.
Note that certain hydrangea types like “Endless Summer” are reblooming hydrangeas. Trim these after they bloom, and they'll flower again in later summer and early fall.
Could non-native annuals eventually become invasive plants?
Q: I love your broadcast, but I was disappointed to see that you suggested people plant non-native species. The country in general and Vermont in particular are struggling with invasive plants introduced from overseas. Even if you say correctly right now that Thunbergia grandiflora will be an annual with changing climate, it could soon be crowding out native plants. - Philip, via email
A: Of course, we want to consider future generations and tread lightly when we responsibly plant. Certain plants that we grow here in our region as annuals are, indeed, considered invasive plants elsewhere. They grow in warmer climates as perennials and can overwinter and self-sow and thus, grow out of control.
Thunbergia grandiflora is hardy in Zones 10 and 11, where it can be aggressive and invasive. When planted in our zones, it will likely not be a perennial here in our lifetimes.
Plants like nasturtiums, lantana and cosmos are all very common annuals here. These are plants that are considered invasive in warmer climates because they can overwinter and crowd out native plants.
We might work, instead, to eradicate invasive plants that are already affecting our region and damaging ecosystems, like buckthorn, Japanese honeysuckle and knotweed — and responsibly plant ones we know won't cause harm.
How to prune inherited and overgrown rhododendron
Q: We purchased a little house recently with a lovely garden and some really established rhododendrons and lots of other trees and shrubs. The rhododendrons are really overgrown and have been neglected. We need to prune one way back. Can you offer tips on how to attempt that and what tools are best to use? - Stephanie, via email
A: You're in luck, because rhododendrons can be pruned pretty severely and bounce back.
Once it's done flowering this spring, go ahead and prune it back by a third to a half of its current size. You'll find using a pruning saw works best, as you'll need to remove some old wood to get it into a nice branch structure.
The rhododendron will leaf out next spring and summer, though it may not flower. Give it another year and you'll have a nicely sized rhododendron with beautiful flowers once again.
All Things Gardening is powered by you, our audience! Send us your toughest conundrums to gardening@vermontpublic.org and join the fun. Or better yet, leave a voicemail with your gardening question so we can use your voice on the air! Call Vermont Public at 1-800-639-2192.
Listen to All Things Gardening Sunday mornings at 9:35 a.m., and subscribe to the podcast to listen any time.
