Waking Up Your Garden for Spring
When Daffodil Hill turns into a sea of yellow, the saucer magnolias shed their fuzzy bud scales, and the robins begin to pull worms from the lawns, I know it’s time to de-winterize my own little backyard garden and get ready for spring.
Even plants that have spent the winter dormant underground sense the warming temperatures and longer days, both clear signals that it’s time to start growing again. Another sign of spring we sometimes don’t fully tune into is the smell of spring soil. Fun fact: As we turn soil over to prepare a bed for planting, we’re releasing geosmin, a compound produced by certain soil bacteria that’s responsible for the “earthy” aroma of soil.
Wherever you garden, there are plenty of tasks to tackle in preparation for the growing season, so dust off your gloves and dig in.
Preparing Beds & Pots
Remember how you mulched your perennials with care and intention last fall? Now it’s time to gently remove that thick layer of organic materials that have blanketed your plants all winter long to give tender new shoots space to sprout.
Picking leaf mulch from around emerging bulbs is a delicate task, and you may find the revealed leaves to be a pale green-yellow color. Don’t worry—they’ll start to produce more chlorophyll and green up quickly. No need to toss those that leaf mulch; just spread it around (not on top of) other emerging perennials. It will slowly break down and add organic matter to the soil.
Many gardeners also start cutting back their perennials around this time of year. If you decided to wait until spring to remove old stems to leave habitat for overwintering garden insects, bravo! To make sure you’re not disrupting anyone’s hibernation spot, wait until soil temperatures are above 50 degrees before getting out the clippers.
(Feel free to wait even longer, if you can. According to the Xerxes Society for Invertebrate Conservation, some bees don’t emerge until May in the Northeast.)
Even if it’s still too chilly to set out tender annuals, you can prep containers and beds for planting.
I’ve found it’s okay to use the same potting soil in containers for 2–3 years, amending each year by mixing in a couple inches of compost. Over time, however, the potting media will start to lose its structure and should be replaced. Likewise, gently incorporating 2–3 inches of compost into garden beds will add nutrients for plant health and organic matter for soil structure and water retention.
Replacing media (and thoroughly washing the container) is essential if you noticed signs of disease or fungus last season. Be sure to check that drainage holes at the bottom of your pots are clear before you fill again with new potting mix.
Adding additional mulch works now too, just make sure you don’t add too thick of a layer on top of a still-dormant plant. Mulch can help protect plants from drastic swings in springtime temperature; try to leave some patches of bare soil for ground-nesting bees.
Planning & Sowing
If you’re growing vegetables this year, either in containers or in the ground, planning for succession crops will make the best use of your space. Cornell Cooperative Extension Agency and Grow NYC both have excellent vegetable planting calendars specific to NYC.
For example, sowing early crops like lettuce and radish around the border of a bed leaves space in the center for transplanting tomatoes or seeding summer squash once the warmer weather arrives; by the time your tomato or zucchini plants get larger, you’ll have harvested out those early-spring crops.
In addition to early crops, you can sow native wildflower seeds in spring (if you didn’t already do so last fall). Most seeds will germinate as soon as the soil reaches 55 degrees.
Be vigilant if you want to use a native Northeastern wildflower seed mix. Unfortunately, not all seed companies pack 100 percent native seeds. Only purchase mixes that list out every species, and follow instructions for sowing. It’s tempting to scatter a ton of seeds, but this may leave you with an overcrowded plot.
More on starting seeds:
Seed Starting: Preserving Our Cultures
Germination Test: Are Your Old Seeds Still Good?
Starting an Herb Garden in a Small Outdoor Space
Planning for a succession of blooms or foliage can be tough. Before your herbaceous perennials have fully emerged, you can still see the bones of your garden space and take some time to think about the season to come.
At this time of year, I notice areas that could use more spring bulbs, both in ground and in containers, something I tend to forget about once other plants grow in and fill the garden space. It can help to mark spots with plastic or metal tags, or make a note in your garden journal.
This year, I’m also considering a succession of plants that support native pollinators. Spring-flowering plants in my partly sunny yard and in containers on my stoop include easy-to-grow foamflower (Tiarella cordifolia), native geranium (Geranium maculatum), and fothergilla, followed by mid- to late-season bloomers like mistflower (Conoclinium coelestinum), rudbeckia, and native alumroot (Heuchera americana).
I also plan to replace some existing ornamental columbine with the striking native Aquilegia canadensis and add some butterfly weed (Asclepias tuberosa) to the mix this year!
Assessing Winter Damage & Spring Pruning
Winter damage will depend on the past winter’s weather and the specific microclimate your plant is growing in.
Mediterranean herbs like sage and rosemary can overwinter outdoors in the ground or in containers in protected spots. During more severe winters you may see some dieback, and occasionally the plant won’t make it.
The upside is that both of these woody herbs can handle heavy pruning. Cut away all dead parts, but keep an eye out for green wood or budding further down the stems. Always cut just above new growth.
Late winter/early spring is also a great time to prune most summer-flowering shrubs (such as roses) as well as most coniferous evergreens. However, many species of hydrangea (a summer bloomer) create flower buds in late summer, so should only be pruned immediately after flowering. Similarly, spring-flowering plants (like forsythia) set their flower buds in the previous growing season, so don't prune those until after they bloom. When in doubt, do a quick internet search.
Many of us gardening in Brooklyn have to consider space. Is the plant growing into a pathway? Is it shading out another plant? Growing over the neighbor’s fence? Winter or early spring is a good time to prune your plants down to the size you want them.
If a shrub didn’t flower prolifically the year before, pruning can rejuvenate it—by thinning out thickets of branches, you’ll open up the remainder of the plant to increased airflow and sunlight, which can encourage flowering and fruiting as well as prevent fungal growth.
Another good candidate for severe rejuvenation pruning is red-twig and yellow-twig dogwood. They show the best stem color on new growth, so if the whole bush is full of dull-colored older stems, it’s time to cut the whole thing back to about four inches above the ground.
I take advantage of early spring, just after the leaf buds have sprouted, to prune and reshape my climbing rose. I’m trying to get it to spread almost two-dimensionally along a brick wall that I’ve rigged with lengths of wire. But by the end of each vigorous growing season, it’s way bigger than I want to start with.
I’ll select a few of the best lateral stems, prune out anything that is growing in the “wrong” direction, and, to get maximum blooms, I’ll leave just a few short shoots intact.
Be aware that pruning back old wood doesn’t always result in better blooms. For example, some hydrangea set flower buds on older wood.
Dividing Herbaceous Perennials
There’s no hard and fast rule about when to divide herbaceous perennials (meaning non-woody plants that die back in winter and lay dormant underground until spring), but early spring is my favorite time.
Once new growth starts poking up, you can see the whole crown of the plant, and because it’s only just starting to leaf out, it’s easy to dig up. It’s less stressful on the plant to divide on a cool, overcast day when the soil is nice and moist. For a primer on perennial division, check out this video tutorial featuring BBG gardener Laura Powell.
Even though it can feel like a destructive act, dividing or splitting a single perennial into multiple plants can help the plant perform better. If a plant is blooming less than it used to, if the blossoms are smaller, if it isn’t growing in the middle, or if it’s very leggy (tall, flopping over, needing to be staked), that could be a sign that it will benefit from being divided. Dividing makes more space for roots to grow and absorb nutrients and water, and re-establishes space between plants, which leads to increased airflow and a lesser likelihood of fungal disease.
Sometimes plants (like mint, pachysandra, or ajuga) spread so much they start to take over your container or designated garden spot. As long as they’re not obnoxiously invasive, this is great! You can divide them to manage their size and give away the extras to your friends and neighbors.
Gearing Up for Spring
It’s also about that time for gardeners to shed the layers of clothing that have kept us cozy all winter long. Remember—much like tender shoots, our bodies are new again to the elements. Sunscreen, a hat, and a nice thick hand salve are always a good idea during these first days of a new season.
Enjoy!