For any gardener, high summer is quiet compared to spring or fall, with the requisite cleanup. But while it may not be a time for ambitious planting projects, it is a time for ongoing maintenance — especially chores that pay off long-term.
At public gardens like Untermyer Park and Gardens in Yonkers, N.Y., a 43-acre former estate on the Hudson, it was an eerily quiet spring and early summer without visitors, even before the “summer pause,” as Timothy Tilghman, the head gardener calls it. But there is still work to be done.
“Patrons elevate the standards,” Mr. Tilghman said, but even without them, “a public garden should always be display-worthy.” He keeps his eye on his list of tasks, reshuffling entries as priorities and staffing levels shift.
Almost no one saw the pink-and-purple palette carefully planned to delight early season visitors, although the seeds had been tracked down and propagated. To spare those sweet peas, purple-leaf mustards and violets a fate as compost before their time, the bare-bones crew took some home for private enjoyment, which eliminated one chore — watering them — from their to-do list.
The lockdown did allow a little cheating: The crew left sprinklers and hoses out between waterings of the 2,000 newly planted perennials, rather than dragging them back into storage daily, as they would in a normal year.
But in other ways, the public’s absence got back at the gardeners by creating additional tasks: “We never have to weed our paths, because usually visitors walk on them,” Mr. Tilghman said. “But this year, no feet.”
Perhaps he can cross that job off his list now, as Untermyer reopened on Fridays, Saturdays and Sundays beginning July 10, with timed tickets. Guests are back, and as August beckons, Mr. Tilghman shared his high-summer to-do list.
Water and Weed Consistently
“If you can’t enjoy weeding, you won’t be a happy gardener,” said Mr. Tilghman, citing its importance to a garden’s health and visuals. “Everyone enjoys the neatness of a fresh planting, but unless you’re willing and eager to get in there and weed …”
Deep, diligent watering, like weeding, is also crucial. (Although after each session at Untermyer, the gear must once again be stowed.)
And while you’re tending to both: Observe and make note of what needs fixing.
“We look for scale, vigor, composition — and aesthetic worthiness,” Mr. Tilghman said. “Does a plant look good in the border, and is it worth growing?”
Sometimes what was irresistible in a catalog isn’t as appealing in your garden. “Once established, maybe it doesn’t add a strong visual element, or it’s too compact — or colonizes when you didn’t expect it to,” he said.
At Untermyer, those insights become essential fodder for action plans in the fall and the following spring.
Deadhead and Groom
Untermyer’s lavish annual and tropical schemes in beds and pots are deadheaded regularly and pinched back for scale. But not just the annuals.
Some shrubs, including messy-looking spent roses and even certain hydrangeas, also need grooming.
“While most hydrangeas look great through winter, some don’t,” Mr. Tilghman said. “The arborescens flowers that won’t look good dry and tawny, and pull the plant down into a flattened mess — they get deadheaded, too,” along with any floppy blue mopheads or macrophyllas.
“We’d rather have nice green shrubs,” he said. “Thankfully, the oakleaf types, you usually don’t have to touch.”
Or Plan to Save Seed
Some annuals self-sow if they are allowed to set seed — including Nicotiana, Verbena bonariensis and annual poppies. So don’t deadhead every last fading flower as late summer approaches.
“When I go into a nursery and there’s a flat of 12 seedlings at $ 5 a plant, I just can’t buy it,” Mr. Tilghman said. “With the really prolific self-sowers, it’s much more economical to gather seed this summer and fall — or just plan to leave plants in place to sow themselves.”
Don’t Forget to Edge
Attention to detail was instilled in Mr. Tilghman when he worked for Marco Polo Stufano, the founding director of horticulture at Wave Hill, a public garden not far down the Hudson, in the Bronx.
“A secret: You can make your garden look pretty good, no matter what’s really going on,” he said, “as long as path and bed edges are crisp and weed-free. Marco used to remind us that ‘God is in the edges.’”
Although the traditional method involves the use of an edging tool or spade, or even sheep shears to clip errant grass, Mr. Tilghman automates the process (always wearing eye and ear protection): He turns a weed whip, or string trimmer, 180 degrees to cut a vertical slice rather than a horizontal one. The trigger will be on top of the pole, meaning you use your thumb to operate it.
“Rather than working in a sweeping motion,” he said, “I put the motor against my hip, so I’m not moving the whip, but slowly walking with it in position.” It takes practice, but is a timesaver.
“I got yelled at the first time I did it at Wave Hill, but then Marco followed me around for a minute and acknowledged it wasn’t as good, but good enough — which I took for an approval.”
There’s a Right (and a Wrong) Way to Mulch Around Trees
A ring of mulch right out to the drip line is better for a tree than ground cover or even grass, which compete for moisture and nutrients.
Untermyer’s two most important trees, old weeping beeches, had been underplanted with pachysandra, which Mr. Tilghman removed in favor of mulch. But just two or three inches, no deeper — never the dreaded “volcano mulch” — and never mulch against the trunk, where it can harm the bark and invite decline.
“If you do have ground cover growing around trees,” he said, “this is a good time to edit and get it six to 12 inches away from the trunk, like the mulch.” Rodents love to tuck in and gnaw on bark, especially in winter.
Summer-Prune That Wisteria
Rampant vines like wisteria — which got their precise, hard pruning at Untermyer back to three to five nodes for each strong shoot in late winter — need touch-ups once or twice in season.
“It’s so vigorous it outgrows its space, and just looks bad,” Mr. Tilghman said. “We don’t cut back as far as the detailed March pruning, but we keep it from going wild.”
Lusty climbers like Dutchman’s pipe (Aristolochia) and trumpet vine (Campsis) also benefit from pruning. And with the trumpet vine, he said, “look for any growth coming up from underground runners now, too, and cut it out.”
Other summer-pruning targets include fruit trees. At Untermyer, Mr. Tilghman identifies and removes any bad branching in the ornamental cherries and other trees, including suckers at the base, vertical shoots jutting up off branches and inward-facing or crossing ones.
“Sometimes it’s easier to prune for shape and scale when you see the plant in leaf,” he said. “Some structural cuts may sacrifice a little spring show, but it’s healthier for the tree than getting more overgrown.”
He added: “Any textbook that gives you the exact right time to prune each plant is leaving out something: Realistically, sometimes you just have to do it when you have time.”
Sometimes Simpler Is Better
For all Untermyer’s artful plant combinations, sometimes simplicity is preferable. Are there places in your garden that need quieting?
The Vista, one the garden’s most important Hudson views, is embellished by ancient Roman columns installed by the long-ago property owner, Samuel Untermyer, and beyond that, by the river and rugged Palisades.
The team created an allée of 99 Cryptomeria and, beneath them, twin stretches of golden Japanese forest grass (Hakonechloa macra Aureola). Both plants have year-round appeal and neither distracts from the real show. Instead, they frame it.
“On any main axis or transition moment within a smaller garden, or anywhere you have a bigger view,” Mr. Tilghman said, “an overly fussy planting can actually compete and add visual static. Let the big moment nearby show.”
If There’s a Break in the Heat, Prep Future Beds
That weedy spot out back you’ve been meaning to start over on, or the new bed you’ve been imagining? If the heat relents even briefly, push through and prep them.
The Untermyer crew did that and more in August 2018, in the former estate gatehouse that is now the Ruin Garden. Because the estate and its gardens had been abandoned and in decline for decades before being rescued in 2011, a major cleanup was required.
“Hopefully, your task will not be quite as daunting,” Mr. Tilghman said. “We had soil full of trash, broken bottles — so we had to excavate three-plus feet and build it back up.”
What they didn’t remove: the graffiti on the walls. It remains as a testament to Untermyer’s incredible history.
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