Don’t Make These 12 Pruning Mistakes in March, Especially if You're a Beginner Gardener

There’s nothing difficult about pruning, but there sure is a lot that can go wrong while you’re learning how to do it. Honestly, I used to have pruning anxiety every single spring, worrying whether I was unwittingly snipping off this summer’s flowers or – far worse – inadvertently murdering my precious plants. Yes, I'd acquainted myself with the only pruning rule I needed to know (those legendary three Ds), but what about all the pruning mistakes I was supposed to not do? It scared me silly.

So here’s the help that I wish existed when I began gardening decades ago. It’ll speed you straight up the learning curve so you can get your spring pruning done confidently, and know you’re helping rather than hindering your plants. And then, I promise you, pruning is such fun, slicing out diseased stems like a heart surgeon and shaping just-right silhouettes like a hairdresser. It’s so satisfying seeing a plant you’ve pruned bursting back into life and growing more blooms than ever before, too.

Please don’t worry a jot if you discover you’re guilty of any of these errors, because you’re certainly not alone. I’d wager that each and every gardener – myself included, obviously – have committed all these crimes against cut stems in their past. Rest assured, plants are amazing things, and pretty hard to kill no matter how poorly you prune them. But get all the basics right by avoiding these common slip-ups, and your plants will be healthier and happier, with strong growth and beautiful blooms. And you'll feel better, too. Here are the biggest mistakes not to make…

1. Making Straight Cuts

There’s a very good reason why every pruning article advises making angled cuts when you’re pruning. Snip straight across a stem and, when it rains or there’s a heavy dew, water may pool on the fresh cut, slowing healing and potentially leading to rot or disease. Make an angled cut, however, and moisture will quickly run off the stem end. You don’t need to be too exacting but aim for around a 45° angle.

It’s also a smart move to angle the cut away from the bud below, so as not to risk damaging it. This means that the highest tip of the cut stem should be on the same side as the bud below it. An easy way to remember this is to angle your cuts in the same direction as the bud below is pointing.

2. Cutting Off This Summer’s Flowers

You won’t kill a plant by doing this but boy, is it disappointing. By and large, it’s summer-flowering shrubs that you need to prune in late winter or early spring; for plants that flower in spring, wait until after they’ve finished blooming to prune. Monty Don’s rhyme makes it easy to remember, though it needs a little translation over the many zones in the USA: “if it flowers before June, do not prune.”

Of course, there are exceptions, notably around hydrangeas. Here you need to know whether your hydrangea is one that flowers on new wood (in which case you should prune it now for fresh stems that will grow lots of flowers) or one that flowers on old wood (which has already grown its flower buds, so you need to leave it till after it’s bloomed). It’s super-easy to work out which is which with this simple check, then you can cut with confidence.

3. Not Watering Afterwards

Pruning stresses a plant, so it’s important to ensure it’s properly hydrated to cope. Always give your plant a thorough, deep watering after you’ve pruned to help it recover, unless the ground is already full of moisture from recent rainfall.

4. Using Hand Pruners for Everything

We all love our faithful hand pruners but, if you’ve sharpened the blades and you’re still struggling to cut through a stem, you’re using the wrong tool. Why is that important? Because if you can’t cut easily through a stem, you’ll likely crush it and cause it to rip around the edges, which slows healing and increases the risk of disease.

Bypass hand pruners are a great choice for stems as thick as your index finger. If a stem is wider, or is tough and woody, then a pair of long-handled loppers will give you far more leverage. And, on stems any bigger than 1½”, you should be using a pruning saw.

If you have small hands, arthritis, or simply don’t want to exhaust your wrists, get a pair of hand pruners with added power, even for small stems. Ratchet Pruning Shears like these from Amazon use leverage to as much as triple your hand power by letting you cut through a stem in stages. Or upgrade to powered pruning shears with rechargeable batteries such as these from Amazon.

5. Simply Snipping Off All the Ends

Not all stems are equal when you’re pruning. As well as encouraging new growth, spring pruning is an opportunity to direct energy into the plant’s strongest stems to create a robust skeleton that can support all the flowers and foliage to come. So be selective: snip off the weak stems entirely, and shorten the stronger stems.

6. Not Being Brave With Hard-Prune Plants

Some fast-growing plants that flower on new wood, like butterfly bush and hardy fuchsia, need a hard prune in early spring to get the best results. This can mean cutting the stems to stubs a few inches from the ground. Not many plants need this treatment, but those that do really benefit from a harsh cut, so it’s worth learning if you have any in your garden, and then being brutal!

7. Cutting Too Close to the Bud

The reason we snip just above a bud is so the plant can direct its energy into healthy new growth from that bud. Cut too close, and you risk damaging the all-important bud. But cut too far and you’ll leave a stub of stem that will quickly die, inviting disease. The optimum spot is ¼ inch above the bud for most stems. For thicker stems, a handy rule uses the stem diameter to work out the best distance to cut above a bud: the cut should be a quarter of the stem width above the bud.

8. Using Blunt Tools

Hand pruners and loppers that aren’t sharp crush stems rather than slice through them, as I learned when I tested out whether or not the tin foil trick to sharpen secateurs works. Before you prune – but particularly in spring when you’re likely to be cutting tough, woody stems – always, always sharpen your tools. It only takes two minutes, and clean cuts heal faster for healthier plants. If you’re not sure if your pruners need sharpening, then they absolutely do!

A multipurpose tool sharpener like this from Amazon will keep all garden blades sharp, while a pocket-sized sharpener like this, also from Amazon, is handy for on-the-go resharpens mid-pruning session.

9. Pruning to an Inward-Facing Bud

Imagine that a plant has a finite amount of energy in its stems. If you chop off the end of a stem, that energy will go into the highest bud, and the plant will grow a new stem in whatever direction that bud is facing. This means you can easily direct the growth of your shrub. Cut just above inward-facing buds and your plant will grow lots of new stems towards its centre, increasing congestion and the potential for rubbing stems to damage each other, and reducing airflow so heightening disease risk. Cut just above outward-facing buds, however, and you’ll create an open and airy, healthy shrub.

You can also use this know-how to improve the shape of your shrub, or fix problems. Perhaps you’ve had to cut out a dead stem that didn’t survive the winter chill, and its absence has created an ugly gap? Simply choose a bud that’s facing in the right direction and snip just above it to encourage a replacement stem to grow and fill the space.

10. Damaging the Branch Collar

A branch collar is the slightly plump, raised or wrinkled section where a branch joins the trunk or its mother branch. Chop into this swollen area and you’ll damage protective tissue that aids healing and the shrub will struggle to close the wound, leaving a potential entrance for disease. So, when you’re advised to ‘cut flush with the trunk’, for example if you’re removing a weak or damaged stem, be careful not to cut into this area.

11. Chopping Too Much Off an Old Plant

When you’re pruning a mature, neglected tree, shrub or vine, it’s so tempting to chop all the unruly stems off and start again. But if you do that, you may shock the plant, and recovery will be tough. It’s far better to reshape an old plant over three years. As a general rule of thumb, unless it’s a species that can take hard pruning, you should only reduce the overall growth by a third. This could mean that you reduce the plant’s height by a third or, if it’s a multi-stemmed shrub like an American beautyberry, hard-prune a third of its stems to around a foot off the ground.

12. Sealing Stem Ends

There are plenty of pruning wound sealants and dressings on the market but it’s best to let cuts heal naturally. There are a few specialist circumstances where wound sealants are helpful, but that’s best left to the professionals. To help ends heal, all you need do is prune on a dry day, when healing happens faster and it's harder for fungal spores and bacteria to spread. It's also a good idea to disinfect your cutting blades – definitely between plants but, if you're cutting out any diseased sections, after every cut. The best way is to dip them in isopropyl alcohol, available from Amazon (any percentage from 70% upwards is fine).