Native Plants Can Fit Into Small Gardens

Gardening with native plants doesn’t require large open spaces to work in, as the next speaker in the Horticultural Alliance of the Hamptons monthly lecture series will demonstrate. Horticulturist Michael Hagen will share native plant suggestions for rock gardens, containers, crevices, troughs and other small spaces when he speaks in Bridgehampton on Sunday afternoon, November 10.

Compact native plants offer environmentally conscious gardeners more opportunities to create pollinator gardens and provide ecological services. During an interview on Friday, Hagen spoke about taking an approach to ecological gardening in small spaces that has a greater chance of being successful and will benefit wildlife — while also accounting for deer pressure.

Hagen is the curator of the Native Plant Garden and the Rock Garden at the​​ New York Botanical Garden, where he has worked for 10 years. He previously spent more than 12 years as the staff horticulturist at Stonecrop Gardens, a public garden in Cold Spring that started as the private garden of Frank Cabot, the founder of The Garden Conservancy. Hagen is also an adjunct professor at Westchester Community College where he lectures on sustainability, native plant propagation and gardening with native plants, and he’s an institutional conservation officer for the nonprofit Center for Plant Conservation, which works to save rare plants from extinction.

When people think about native plants, they often think about larger areas, like putting in a meadow or big woodland garden or even a border, Hagen said. “People don’t often have that kind of space available. So this talk is really focusing on how you can add ecological services in a relatively small garden space where you don’t have the opportunity of growing a big area of wildflowers, but you also want to support bees and other pollinators that are coming into the garden.”

He said that the problem with many plants available commercially is that they don’t have a lot of ecological function, for a variety of reasons. For example, he said, they may be hybrids or double-flowered so they don’t produce nectar or pollen.

Meanwhile, native plants provide food and habitat for pollinators and for the insects that become nourishment for baby birds.

“People do, I think, have a better understanding nowadays of the importance of growing native plants,” Hagen said.

He finds that the main goals of the home gardeners he speaks to are to provide more ecological services and grow something deer won’t eat.

In the Northeast in particular, finding native plants that are resistant to deer browsing is a priority for native gardens. Hagen said that when deer are hungry enough, they’ll eat anything, but the plants that are most likely to dissuade deer have a spiky texture and rough mouth feel.

“So grasses, sedges, ferns, are all very, very good choices,” he said.

He noted that it’s more difficult to find deer resistance in flowering plants, but anything in the mint family, with a pungent flavor, is unappetizing to deer.

“If you have a high deer population, they will very often kind of chew it and take the buds off without actually damaging the whole plant. But that really doesn’t help if you want to get something to flower,” he said.

For rock gardens, Hagen shows Northeast gardeners that they don’t have to rely on plants from the Rocky Mountains or the Himalayas.

“There are a lot of native plants that are quite well adapted to these kinds of environments, just not obviously so,” he said.

They may be found in pine barrens or Appalachia, and he said they respond well to extremely difficult conditions.

A traditional rock garden — as popularized in the Victorian era and on the East Coast after World War I — is an alpine garden, with flora that’s grown in the Alps, Hagen explained.

Even back then, plant people were making the same observation that’s made today, he pointed out: We don’t have a great climate for growing high mountain plants, whether they are imported high mountain plants or native North American high mountain plants.

“Our weather patterns are just not right,” he said of the Northeast. “We can have very, very variable weather, as you see now. We don’t have reliable snow cover anymore. It can be extremely cold in late winter, early spring, and we can go into periods of drought during the summer. And that can vary from year to year.”

Because Long Island soil is sandy, it is well draining soil, which is good for alpine plants. But Long Island does not have limestone soil, which alpine plants evolved in. That doesn’t mean a rock garden is a bad idea on Long Island; however, it does mean high mountain plants are not the right choice for a Long Island rock garden.

“A lot of our native species are actually stress-adapted species in one way or another, just in different ways than typical rock garden plants,” Hagen said.

Rock garden plants will die if they get too much water, too many nutrients and, in some cases, too much sunshine, he said. So suitable rock garden plants are ones that naturally thrive with little moisture and in low-fertility soil.

One plant he recommends is Phlox sublata, known as moss phlox and creeping phlox. It’s a native plant with flowers in a wide range of colors: pinks, reds, blues, white.

“For the most part, the best way to provide diversity is plant different colors,” Hagen advised.

In his teaching role at Westchester Community College, Hagen most recently taught a course on native plant propagation, focusing on the particular germination demands of certain native seeds and demystifying the process. In ecological restoration projects, where maintaining biological diversity is among the goals, propagating via seed ensures genetic diversity is protected, for more resiliency. But Hagen says for a home garden, that is not a concern for most people, who are not attempting ecological restoration toward pristine habitat.

Home gardeners can build their collection of native plants through clonal propagation — using cuttings and divisions.

There is a time and place to look for locally sourced, phenotype-specific plants, such as while gardening in close proximity to an undisturbed natural area, he explained. For most anthropogenic habitats — environments that have changed due to human activity — that have a lot of generalist pollinators, it’s not much of an issue, he said.

Anthropogenic soils won’t be suited to native plants, Hagen said. “The fertility is going to be different, the structure is going to be different, the microbial community is going to be different. So native plants are going to respond to that soil community, that soil profile, in different ways than they would if you were looking at a pristine, undisturbed natural habitat.”

He advised picking native plant cultivars that do better in slightly richer soil, and said some cultivars are very close to the species of plant they are revised from, but given a snazzy name that makes the plant more marketable.

While straight species may be the best picks for promoting ecological services, they are not always going to be best suited to the soil where a gardener is planning a native garden. And he acknowledged that as gardeners want to add native plants for the sake of the ecosystem, they may want to keep their roses and peonies in their gardens as well. He doesn’t frown upon that.

“The perfect is always the enemy of the good,” he said. “I always believe that purity tests never end well. You really kind of have to be quite flexible about what you’re growing.”

One of the oft-touted benefits of native gardening that Hagen does not subscribe to is that it is very low maintenance compared to traditional ornamental gardening.

“Once you’re buying into gardening, you’re buying into the concept of maintenance,” he said. “It’s just a different kind of maintenance that we’re asking you to do with these native plants.”

Yes, native plants require little to no water once established and no supplemental fertilizer. But they still need attention.

Native gardening requires being thoughtful about plant selection and spending more time in the garden making observations, according to Hagen. “Look at your plants and see, are the pollinators being attracted to your plants? Do they come to this particular plant instead of this one? Are they more attracted to this particular color or the other one? So we’re kind of really asking people to be more mindful and more engaged with their gardens, rather than just plant them or walk away and think, ‘Oh, well, I’ve done a good thing. I don’t need to do anything.’ Because you do. You need to go out there and say, ‘Okay, well, this plant shouldn’t be here. I’m going to edit this.’”

The goal is to put a native garden onto a trajectory of a self-sustaining plant community that will regenerate and self-seed without the need for new plants to be installed every other year.

Michael Hagen will present “Native Plants for Small Spaces: Rock Gardens, Containers, Crevices, and Troughs” on Sunday, November 10, at 2 p.m. at the Bridgehampton Community House, 2357 Montauk Highway, Bridgehampton. Admission is $10, or free for members of the Horticultural Alliance of the Hamptons. Visit hahgarden.org to learn more.