Fall brings out my outdoor neat freak. I feel an intense need to get things buttoned up in the yard before the cold hits. After the annuals and vegetables have come down, I find my eyes wandering to the shrubs and trees. While I understand the desire to clear up the scrub and deadwood to make your yard tidy before the winter, for some shrubs and trees it could come back to bite you in the spring. Here are the shrubs you should (and shouldn’t) prune in the fall.
What bushes you shouldn’t prune in fall
Know your hydrangeas
Ball hydrangea types benefit from being pruned back. Anything up to ⅓ of the plant is considered safe, and it’s not just hacking it back from the top. You want to get into the woody stems and make sure you’re creating airspace in there. However: This is not true of panicle hydras or lacecap hydras, including oak leaf hydras. If you don’t know kind what yours are, you can tell by the shape of the bloom: If it’s ball-shaped, you’re good to prune. If it is elongated, that’s a panicle, while Lacecaps or Mountain hydrangeas have a center of small little balls and lacy blooms around the outside.These hydras bloom on old wood, so cutting anything away is just spoiling next year’s blooms.
Shrubs that bloom on old wood instead of new
Panicle hydrangeas aren’t the only ones, lots of shrubs only bloom on old wood, meaning the stems that look brown and woody. Others bloom on the green new wood that grows every year. Learning the difference is helpful, and lots of people only learn the hard way.
Forsythia, which has yellow blooms in early spring, is another old wood bloomer. You have to prune it in late spring to shape it. Pruning it now would kill your future blooms. The same is true for lilac, rhododendron, and azalea,
Magnolias don’t much enjoy being pruned, but if you do so, it should be after the bloom in spring. Taming spirea, which grows quite quickly, can look tempting to neaten in fall, but that should wait until after the spring.
Flowering fruit trees need a break before pruning
Some plants can’t afford cuts that expose them to virus and fungus right before winter, and that includes flowering peach, cherry, and plum trees. Even your producing stone fruit trees should be left alone until they’ve gone dormant, but flowering fruit trees need to wait until after the bloom in spring. Only apples and pears should get a fall pruning—after the harvest.
The shrubs and vines safe for fall pruning
If you have buddleia (butterfly bush), it forms blossoms on new growth, so fall is the right time to get those pruners out.
By fall, gardenia should be dormant and ready to prune back any deadwood.
Roses need to wait for late fall, but at that point, can be dramatically cut back, and usually need to be.
Summer and fall blooming lavender should be cut back as much as ⅓ every fall after the bloom.
The blooming season tells you what’s safe to prune
With few exceptions, plants are fall or spring blooming. Generally speaking, you prune after a bloom, so plants that bloom in spring get a late spring/early summer haircut, and the same is true for fall bloomers.
That said, every plant has a different growth habit, and while it might be overwhelming to learn about every single plant in your yard, you can slowly build a knowledge base as you go. The authority used to be books like the Sunset Gardener series; Now, you have the internet at your disposal to find specific instructions for every single plant, in whatever format you like. Having good garden tools (like a great pair of pruners) is also essential, as is making sure you clean and sterilize them between plants.
Rain and constant dampness is a threat
Fall is tricky because of the heavier rain and variable temperature. It’s not so cold yet that viruses and funguses struggle, and the constant moisture gives them the perfect environment to thrive. So it’s often best to prune in winter, once plants are dormant, for that reason, and in late spring/early summer, when it’s generally not as wet. That’s the trick, really, to understanding your plants—paying attention to the climate.