May hits you like a freight train in the garden.
One day you are waiting for the late frosts to pass, and the next, everything is overgrown and screaming for your immediate attention.
My lower back is already throbbing just thinking about the sheer volume of work waiting outside.
You step out the back door, the rich, almost sour smell of damp spring compost hits your nose, and you realize the to-do list just tripled overnight.
It is a month of relentless, chaotic biological growth.
This is also the time of year where I usually make my biggest, most painful mistakes if I let the panic set in and rush my work.
I still wince remembering the spring of 1998.
I took a pair of poorly sanitized shears to my first rare orchid collection, overwatered the pots in a blind panic to compensate for a bad cut, and watched root rot turn them to mush in a week.
Gardening is often a messy, unforgiving business.
You are managing biological life and death, and weather does not care about your weekend plans.
But right now, we need to focus on the reality of your spring maintenance list.
If you ignore the 12 plants to prune in May detailed below, you will pay the price with leggy, unproductive shrubs and zero flowers next year.
1. Forsythia
These early-blooming yellow shrubs are loud heralds of the new season, but by late spring, they just look like unruly green mops.
You must cut them back immediately after the last faded flowers drop to the soil.
If you delay this job until July, you are actively chopping off the new buds developing for next year.
I usually take a folding saw and remove about a third of the oldest, thickest wood right down at the soil line.
It takes serious elbow grease, and you will almost certainly scrape your knuckles on the surrounding rough bark.
But this harsh cut forces fresh, vigorous shoots from the bottom, stopping the plant from turning into a top-heavy, woody nightmare.
2. Lilac (Syringa)
Lilacs smell fantastic for about two weeks, and then you are left staring at brown, crusty seed heads for the rest of the year.
Tidying these up is a priority, but you must do it carefully.
The delicate new buds are sitting right beneath those spent, ugly flowers.
Snip just the dead flower head off with your secateurs, making sure to leave those two plump little green buds entirely intact.
While you are wedged in the middle of the shrub, cut away any dead or actively rubbing branches.
I routinely find the powdery, white dust of mildew on the inner leaves during wet springs, which is just another frustrating reality of growing these particular shrubs.
Thinning the congested center improves airflow and gives you a fighting chance against fungal spread.
3. Early-Flowering Clematis (Group 1)
Clematis varieties like C. alpina and C. macropetala finish their main display by mid-spring.
The Royal Horticultural Society officially categorizes these into “Pruning Group 1,” which simply means they flower on last year’s mature growth.
You do not strictly have to prune them, but if you skip it, they quickly turn into a tangled, suffocating bird’s nest.
I spent three miserable hours yesterday wrestling with a ten-year-old vine that had swallowed a wooden trellis whole.
Cut back the flowered stems to a pair of healthy nodes to keep the sprawling beast contained.
It is tedious, neck-cramping work tracing those brittle vines back to a viable bud, but it beats having the entire structure collapse under heavy snow next winter.
4. Spring-Flowering Spiraea
Varieties like the bridal wreath (Spiraea arguta) finish their cascading white blooms as the weather warms.
Once those tiny petals drop, they stick to absolutely everything, turning into a mushy paste on your leather gloves.
When I was studying structural pruning techniques at the Royal Botanic Gardens, Kew, an older groundskeeper taught me never to be timid with these.
Get in there and cut the recently flowered shoots back to strong, outward-facing buds.
Then, remove a few of the oldest, darkest stems right down to the ground level.
This prevents the shrub from becoming a dense thicket of dead twigs that snag your clothes every time you walk past it.
5. Mock Orange (Philadelphus)
Actually, wait.
If you have a late-blooming variety, don’t touch it quite yet.
But for the early bloomers, the end of the month is often your only window to tidy them up before the wood hardens off.
This shrub gets terribly congested at the base.
Every single year, I drag out my heavy loppers and curse under my breath as I try to reach the dead center of the plant.
Take out roughly a quarter of the oldest stems at the base to open it up.
You will likely find sticky aphid colonies huddled on the fresh green growth while you work.
Just squish them with your thumb or blast them off with the hose, though my hose inevitably kinks right as I finally get the water pressure going.
6. Weigela
Once the pink or red trumpet-shaped flowers fade and drop, it is time to act.
Weigela primarily blooms on the sturdy wood produced during the previous growing year.
Cut back the specific stems that just finished flowering by about a third, stopping just above a healthy side shoot.
Then, push your arms deep into the base of the shrub and completely remove one in five of the oldest stems.
You will get damp soil jammed under your fingernails doing this.
However, it forces aggressive new growth from the base that will carry next year’s blossoms.
7. Japanese Kerria (Kerria japonica)
Those bright yellow, pom-pom flowers might look cheerful, but the plant itself is a territorial thug.
It spreads via aggressive underground suckers and will choke out its weaker neighbors if you turn your back for a season.
After it finishes blooming, cut the flowered canes back to a strong vegetative bud.
More importantly, take a heavy, sharp spade and physically sever those invasive suckers at the root.
You will feel the physical jar in your shoulders every time the spade hits a hidden rock.
It is back-breaking manual labor, but if you skip this step, you will lose your entire garden bed to a sea of green canes.
8. Flowering Currant (Ribes sanguineum)
This early bloomer is a vital magnet for waking pollinators, but it gets scruffy and woody very fast.
Prune it decisively right after the hanging pink flower clusters drop away.
I learned a hard lesson about neglect in 2005 when I lived in a harsh, dry climate.
I was obsessed with acclimatizing delicate tropical plants I had studied during a sweaty, humid trip to the Singapore Botanic Gardens.
I focused all my energy on fighting the dry air for the tropicals and completely ignored my foundational shrubs.
The tropicals died anyway, and the currant took three grueling years of restorative pruning to recover its natural shape.
Cut the flowered stems back to a strong outward-facing bud, and saw out any crossing branches that cause friction wounds.
9. Flowering Quince (Chaenomeles)
The rigid, thorny branches on this particular shrub make pruning a miserable, blood-drawing task.
Wear your thickest, stiffest leather gloves.
After the spring floral display finishes, grab your secateurs and spur-prune the side shoots back to two or three leaves.
This specific technique encourages the formation of tight fruiting spurs for those hard, bitter little quinces later in the autumn.
Do not touch the main structural framework branches at all.
Only remove framework wood if it is visibly dead, cracked, or actively diseased.
10. Early Viburnums
Spring bloomers like Viburnum x burkwoodii or Viburnum carlesii require a much lighter touch.
They simply don’t need the aggressive butchering that a fast-growing Forsythia does.
Just trim back the exact stems that flowered to a healthy, plump pair of leaves.
I usually spend this time on my knees looking out for the dreaded viburnum beetle larvae.
If you see leaves that look like skeletonized, brown lace, you have a severe pest problem that a pair of shears won’t fix.
Sometimes I think gardening is largely just tedious pest control with a better PR department.
11. Rosemary
This is the month I finally assess the lingering winter damage on my woody Mediterranean herbs.
By now, you can clearly see which branches survived the winter frost and which are brittle, grey, and dead.
Cut out the dead wood entirely, taking it back to healthy green growth.
Then, give the rest of the surviving plant a light, shaping trim.
Never cut hard into the old, brown, leafless wood.
If you do, the plant will likely refuse to resprout and will just die out of sheer spite.
12. Boxwood (Buxus)
Late spring is traditionally the time for the first major hedge trim of the growing year.
Always wait for an overcast, dull day to do this, as bright sun will heavily scorch the freshly cut leaf edges.
However, pruning boxwood feels like a depressing gamble these days.
Between ravenous box tree caterpillars devouring the foliage and box blight turning entire hedges brown overnight, keeping them alive is exhausting work.
According to the Missouri Botanical Garden’s plant disease guidelines, you must strictly sanitize your shears between cuts to prevent spreading fungal spores.
I keep a dirty rag soaked in rubbing alcohol in my back pocket while I work down the hedge line.
It smells clinical, ruins the denim of my jeans, and slows me down, but it is the only way to save the plants.
The Messy Aftermath of the Chop
When you finally finish tackling these dozen plants, your yard will look like a localized war zone.
There will be uneven piles of sappy green waste scattered everywhere.
Your forearms will be covered in red scratches, your back will ache intensely, and you will probably have crushed a snail or two under your heavy boots.
This is the gritty, unglamorous reality of the craft.
You have to rake it all up, drag it to the compost bin, and then spend another tedious hour cleaning the sticky sap off your tools.
If you leave wet plant sap on carbon steel blades, they will rust solid by Tuesday morning.
Take a deep breath, grab a stiff brush to scrub the dirt out of your fingernails, and know that you did the necessary, ugly work.
Because without putting in the hard labor to manage your 12 plants to prune in May, the garden of July is just a chaotic, overgrown mess.