Expert advice: A Northeastern horticulturist’s guide to prepping your garden
Here is Kelly Young’s checklist for how best to prepare for a successful growing season in your ornamental garden.
It’s tempting fate to say spring has officially arrived in New England.
But look closely, and the first signs of the season are already there: the witch hazel is in bloom, the first bulbs are poking through the soil, and horticulturist Kelly Young is busy preparing the ornamental gardens on Northeastern University’s Boston campus.
Young has a big task.
The Boston campus is an arboretum, after all, and has more than 11 acres of greenspace.
The past winter was also rough. With deep freezes, premature thaws and precipitation of all forms, Mother Nature used her full arsenal over the last few months.
“Even some of the supposedly cold-hardy species took a hit,” Young says.
Meanwhile, the calendar will soon flip to commencement season, which is when the campus reaches its aesthetic peak.
But the spring cleanup can be a daunting task (or a daunting landscaping bill) for any gardener.
Here’s Young’s checklist for how best to prepare for a successful growing season in your ornamental garden.
1. Prune
You can start pruning in late winter and early spring, Young says, and she recommends first assessing the plant you are pruning and its specific needs.
After you’ve got your plan, start with removing the “Three Ds” — dead, damaged or diseased wood — from shrubs and ornamental trees.
But be sure to consider bloom time: dogwoods, magnolias, cherry trees, lilacs, rhododendron and other spring flowering woody plants have already set their buds — don’t cut off this year’s flowers in your effort to clean up the yard. These are best to prune after they have flowered.
2. Cut back standing perennials and grasses
It is increasingly common for gardeners to leave some perennials and ornamental grasses standing through the winter to provide visual interest as well as habitat and food for animals. But they’re looking a bit scraggly by now. So, time to cut them back and allow them to focus energy into new growth.
How to tell where to cut back? Again, first use the “Three D’s” and remove dead, damaged or diseased foliage. Then look closely.
“The plant kind of shows you what it needs,” Young says.
She pointed out “tired and winter-damaged” liriope (a groundcover with grass-like foliage) in between Speare Hall and Stetson East this week. She gave it a nice trim to a half-inch or an inch or so above the ground, and suddenly it looked fresh and green.
3. Remove debris
Twigs, stones, leaves and other detritus accumulate in gardens and on lawns over the winter, whether courtesy of Mother Nature’s storms, snow shoveling or other human activities. Many gardeners are also keeping leaves in beds over the winter for insulation and to provide habitat for critters.
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Now is the time to get all that out of there. The sun needs to warm the soil, plants need the light to start to grow — and it’s a lot easier to do it now than trying to do it around maturing perennials.
And while you’re at it, also chuck out any early season weeds and look for pest activity — better to catch them early, Young says.
4. Assess the soil
Do you need to till the soil to get better aeration and drainage, or maybe add compost or manure for nutrients and to incorporate organic matter? Again, it’s easiest to do it now, before things really get going in the garden. A light layer of compost can do wonders for your soil health and for hungry, growing plants. It even mixes in pretty well as the soil expands and contracts from the direct, strong sunlight alternating with cool nights (maybe even frost) and with plants breaking through the surface.
Which brings us to another layer of material to add to the garden: mulch. This can be controversial. Some people love their deep black or red mulch to contrast and make plants really pop. But Young notes that the dyes can leach into the soil from watering. She recommends natural, dye-free mulch about three inches deep to keep the soil cool in the summer, retain water and suppress weeds.
Also, keep mulch away from the base of trees and shrubs. You don’t want a mulch volcano. That’s a rookie mistake, Young says, laughing.
5. Divide late-season perennials
It’s so much easier to divide a hosta when its shoots are just breaking the surface than when it is fully leafed out.
Same with other perennials — usually the ones that flower in the late summer or fall like chrysanthemums, asters, geranium and black-eyed susan. As soon as you start to see new growth forming, you can dig them up to divide.
6. Cut or edge beds
“Planning and creating a clean, tight edge really makes a big difference,” Young says, naming this as one of her favorite spring tasks.
Also, Young recommends gardeners take some time to plan ahead to add to or modify the garden design … and start planning the annuals for those pots and other containers.
Although be warned, you may want to wait until after the last frost for the ones that can’t easily be moved inside or covered with a blanket
“It’s a lot of work you put into annual displays to lose them to a frost,” Young says.