March is a time with big temperature swings across the US, and any pruning plans need to reflect your location and the current weather. Here, we look at some plants to prune in March. We also reveal what to avoid trimming, and the conditions under which you should never take the pruning tools out this month.
Weather-wise, March is late winter for northern gardeners and early spring in the south. There are big temperature swings across the US, including severe weather conditions in the northeast and mid-Atlantic. Elsewhere, the weather remains more typical, with colder weather in northern areas and milder temperatures in southern regions.
Extreme winter temperatures are never a time to prune trees or shrubs, and even in northern and transitional zones, late frosts can still happen and affect new growth stimulated by pruning. However, gardeners in milder climates should be able to prune without such worries. Bearing all that in mind, let’s look at a selection of plants to prune in March as well as those to steer clear of.
Plants to Prune in March
1. Dormant Trees
March is an ideal time to prune trees before they break dormancy, which often happens this month in many zones. There is a wide range of deciduous ornamental and fruit trees to prune this month – our guide to trees to prune in March shows a good selection.
The key to pruning trees is primarily to remove dead, damaged, or diseased branches. And trimming out crossing branches and congested areas promotes air circulation through the canopy, which helps keep the tree healthy.
For whatever reason, when pruning tree branches, avoid making any tree pruning mistakes that cause harm. This includes using the wrong tools for the job, using blunt pruning tools, and trying to remove too large a branch in one go, which often tears or splits the bark.
To prune large branches, take a pruning saw and first make a small cut on the underside a few inches from the joint. Then cut the top a few inches further up the branch to remove the bulk, before tidying up with a last cut at the base.
A folding pruning saw like this one at Walmart is always my go-to tool for tree trimming.
2. Summer-Flowering Shrubs
March offers a window to prune shrubs, but not all (we’ll get to which not to prune later). It is the time to prune deciduous shrubs that bloom on new wood in the summer. These shrubs need pruning before they start growing in spring to develop lots of buds for this season’s blooms.
Summer-flowering deciduous shrubs to prune in March include panicle and smooth hydrangea varieties (but not all hydrangeas), cotoneaster, Russian sage, lavatera, hardy fuchsias, cotinus, and many shrub roses. Lots of these feature in a previous focused piece I wrote on plants to prune in March, with bespoke pruning advice for each.
Again, a primary focus is to remove any dead, diseased, and damaged branches, along with crossing, weak, or congested growth. When pruning shrubs or summer-flowering climbers this month, don’t get too carried away. Observe the one-third pruning rule and don’t remove any more, as it may affect this season’s display.
3. Any Remaining Perennials
Any remaining perennials in flower beds that have not been cut back yet need trimming this month.
The benefits of leaving herbaceous perennials in place over winter include feeding birds and providing shelter for insects in a wildlife garden. But they do need to be cut back before new growth comes through, and the old debris cleared away, as pests and diseases can overwinter on the material.
The likes of sedum, bee balm, hostas, asters, black-eyed Susan, coral bells, coneflower, and many more may need this attention in March. Check before trimming for signs of new growth, and if there are any, be very careful with the pruning shears to avoid new shoots or the plant's crown.
After cutting back, it is a good idea to mulch around plants to help promote strong growth for the season ahead. Use an organic type of mulch, such as compost, leaf mold, or bark chip, such as this bag of organic premium mulch at Amazon.
4. Ornamental Grasses
Ornamental grasses are left standing over winter to provide food and shelter for wildlife, as well as provide seasonal interest. They do need to be cut back ahead of the new season, and March is a perfect time to do it if you still haven’t yet.
When it comes to cutting back ornamental grasses, the method differs depending on the type. But the good news is that both methods are super-simple.
Deciduous grasses, like Calamagrostis, miscanthus, and panicum, want bundling together and cutting 10-12 inches above the ground. This can be done with a pair of sharp pruning shears, and I have had a trusty pair of Felco F2 pruners (you can get Felco F2 pruners at Amazon) for many years for spring trimming.
Whereas, evergreen grasses, such as carex and festuca grass, just need dead foliage removed, and you can do this by combing through the blades wearing a good pair of gloves. A pair of thick leather gauntlet gloves like these at Walmart is perfect to keep you safe when handling grasses.
5. Hardy Evergreen Shrubs
Evergreen shrubs are great picks for year-round structure and screening if you are after shrubs for privacy. While evergreens are low-maintenance shrubs, they do need an annual trim to keep them looking in top shape year after year.
If you live in a milder climate, hardier evergreen shrubs can be trimmed this month before new growth starts. This includes the likes of laurel, euonymus, holly, viburnum, and mahonia.
Often, these shrubs need just a gentle trim to shape them, but you can prune heavily to rejuvenate older, neglected evergreens.
What Not to Prune This March
1. Anything in Freezing Conditions
To put it simply, you don’t want to prune trees, shrubs, grasses, or perennials when you are experiencing severe winter cold weather. Plummeting temperatures, snow, and icy winds all damage plants, as well as people and property.
There are many reasons it would be a pruning mistake to trim in extreme conditions. Not only is it a risk to your own health, but frozen branches are very brittle and will snap rather than cut cleanly.
Furthermore, plants cannot heal wounds at low temperatures, making them susceptible to pests and diseases, and frosts can get into pruning cuts and cause dieback. If you are experiencing freezing conditions, don’t think about pruning until warmer weather arrives.
Once winter storms have passed, you can assess any damage and prune as required. But trimming before the conditions improve can only make things worse for your plants.
2. Anything Ahead of Dropping Temperatures
Things can change quickly at the start of March, so pay close attention to forecasts and don’t prune if the temperatures are set to drop in the coming days.
Late frosts are common, and snowstorms can strike, so if it looks like freezing conditions are inbound, hold off any pruning until it passes and the days warm up.
3. Trees and Shrubs That Bloom on Old Wood
Don’t prune any spring-flowering shrubs that bloom on old wood, as all you’ll be doing is removing this season’s buds and robbing you of a display. This includes shrubs such as forsythia, lilac, rhododendron, flowering cherry, weigela, and oakleaf hydrangeas.
These bloom on old wood produced last season. They developed buds last summer and fall, and trimming now removes the blooms. All these plants want pruning after they have flowered.
This guide to what not to prune in spring contains a long list of plants you ought to keep the pruning shears away from in March.
4. Trees Vulnerable to Silver Leaf
There are troubling fungal diseases around at this time of year, such as silver leaf, which must influence what you prune. It should certainly be a reason not to prune certain fruit trees in March.
Silver leaf is a fungal disease that primarily targets plum, cherry, apricot, and almond trees. Once infected, leaves turn a silvery color, branches suffer dieback, and bracket-shaped fungi appear.
Silver leaf primarily gets into trees through pruning wounds. To keep trees safe, you shouldn’t prune stone fruit trees in winter when the spores are more prevalent in colder, damper weather.
Instead, prune them in summer, when the spores aren’t as common, and the tree is actively growing, so it can heal pruning wounds more quickly.
5. Borderline-Hardy or Tender Evergreen Shrubs
We discussed how you can prune hardy evergreen shrubs this month, but it is riskier to trim more tender evergreens, including those that are borderline-hardy.
Milder and colder regions can still receive frosts in March, and new growth will be damaged as a result. This can leave the shrubs more vulnerable to disease.
Both gardeners and the shrubs are at risk of a false spring, when temperatures rise in late winter, only to drop again. By rushing to trim, it stimulates new growth, which will die back if a late cold snap hits.
For gardeners in colder climates, the safest plan of action with the likes of Mexican orange blossom, camellia, abelia, and Italian cypress is to wait until the days warm up towards the end of the month or in early April.
March is a month when temperatures rise and the days get longer. It is a period when we can now spend more time in the garden, and start thinking about planting in earnest.
To give you some inspiration and tasks to add to your spring gardening checklist, our guide to what to plant in March includes flowers, fruits, and vegetables you can plant or sow this month, along with guidance on whether you should sow them indoors or outdoors.
Love inspiring garden ideas, outdoor advice, and the latest news? Sign up for our newsletter and get the latest features delivered straight to your inbox.
Shop Pruning Tools
This pruning set features bypass pruning shears, bypass loppers, and a folding pruning saw. They all have steel blades and soft grips for comfortable trimming.
