Innholdsfortegnelse for March/April 2020 i Horticulture

What will you plant this spring? We’ve packed this issue of Horticulture with ideas and information to help you answer that question, whether you’re just starting to “think spring” or you’ve been planning for months. Could your landscape use a new tree? The “Plants We Love” column highlights weepers (page 66); “Public Gardens” includes rugged recommendations from the staff at the Utah State University Botanical Center (page 24); and in our new “Expert Advice” column, the Davey Institute’s Chelsi Abbott lists four of her favorite species for gardens North and South (page 12). The professionals at the Morton Arboretum, our other featured public garden, offer pointers on planting a new tree (page 28). Moving to the shrub layer, I checked in with representatives from a couple of the country’s leading…

GIVEN HER MASTER’S DEGREE in plant pathology, you may think Chelsi Abbott, a Technical Advisor at the Davey Institute, is mostly concerned with how trees die. In speaking with her, it quickly becomes clear that she’s happy talking about steps we can take to help trees live—and thrive. This can begin at the earliest start of spring, when it’s time to greet our awakening garden and landscape trees. “Spring cleaning really applies outdoors as much as indoors,” Chelsi says. That means stepping outside “with a keen eye” to assess our woody plants and address routine maintenance, she explains. She recommends looking not just for the obvious—that is, winter-damaged branches—but also searching closely to determine trees’ and shrubs’ health. A good clue comes with leafing out. Chelsi says, “If something’s not…

Every spring we’re asked, “When and how do I prune my lilacs?” Lilacs are a multistemmed shrub, meaning there are many stems, or canes. Each year, the plant should produce at least one new stem from below the soil level. This category also includes red-twig and tatarian dogwoods (Cornus sericea and C. alba), ninebarks (Physocarpus), forsythia and viburnums. As a general rule for when to prune, we use an old adage: “If it blooms before Memorial Day, prune it after Memorial Day. If it blooms after Memorial Day, prune it before Memorial Day.” In reality, all can be pruned in the late winter to early spring, but by following this adage, you’ll enjoy the blooms each year. You won’t cut them off before they bloom. The best method is to…

Spring is one of the best seasons to plant a new tree. Make sure your tree gets a good start: • Match the needs of your tree with the conditions of your site. • Place the tree in a location where it can achieve its mature size. • Call your local utility locator before planting to ensure that the area is free of cables and the roots will have the space they need. • Remove as much of the packaging as possible, including twine, wire and burlap. • Make sure the roots aren’t circling the root ball before planting. If they are, square off the root ball to encourage the roots to grow outward. • Don’t plant too deeply. The area where the trunk widens to the roots should show…

Spring can be a good time to assess a home’s curb appeal. What’s going right or wrong in the planted areas immediately adjacent to the house’s foundation and main walkways? The foundation bed demands selections that won’t grow so tall as to obscure the home’s windows, nor so wide that they cover companions or leave no space for seasonal plantings. Also needed are options with an even shorter stature, so that they suit the very front of the foundation bed, the edge of the front walkway or the space between sidewalk and street. Lastly we’re looking for selections that can stand at the corner of the house, to the side of the doorstep or alongside the lamppost or gateway, because while they grow tall they remain very narrow. BENEATH WINDOWS…

Nancy Cavanaugh, a Horticulture reader, relates her experience growing woody plants in containers: I have been growing several plants in the same container for over 10 years, however I do not replace the soil at the top. Instead I slide the plant out of the container and remove up to a third of the compacted soil and root mass, and add fresh soil at the bottom of the container. On plants such as tropical hibiscus standards, I begin by using a pruning saw to remove about two or three inches from the bottom of the root ball. Then I make three or four evenly spaced vertical slices around the remaining root ball. After teasing several roots free, I remove wedge-shape pieces in proportion to the size of the remaining root…

WHEN SPRING ARRIVES, like most gardeners I’m anxious to start digging in the soil. While I love my long-season tomato and pepper plants, I also appreciate the many vegetables that thrive in the cooler temperatures of spring and become ready to harvest in mere weeks. Here are my top crops to sow a month before the last frost. No spring vegetable garden is complete without a patch of lettuce. It’s quick and easy to grow, and it can be planted in garden beds or containers. Direct sow seeds about four weeks before the last expected spring frost or even earlier in a cold frame or greenhouse. Can’t-miss varieties include Salanova Home Garden Mix, ‘Sandy’, ‘Black Seeded Simpson’ and ‘Red Salad Bowl’. Salad turnips like ‘Hakurei’ have been a spring standard…

Chelsi Abbott, a Technical Advisor at the Davey Institute, holds degrees in plant pathology and biological sciences. The Davey Institute is the scientific headquarters of the Davey Tree Expert Company, whose field crews tend residential and commercial properties across North America. Scientists like Chelsi support Davey’s vast network of tree workers through research, technical support and educational offerings. Learn more about Davey at http://www.davey.com.…

If you’re up for an excursion, Bartram’s Garden is still there in Philly—at 54th Street and Lindbergh Avenue. The garden is a 45-acre National Historic Landmark operated by the John Bartram Association in cooperation with Philadelphia Parks and Recreation. You can see a Franklin tree growing there and at these places: Alabama: Birmingham Botanical Gardens Delaware: Winterthur Museum, Garden & Library Georgia: State Botanical Garden of Georgia (Athens) Illinois: Chicago Botanic Garden (Glencoe) Massachusetts: Arnold Arboretum (Boston) Missouri: Missouri Botanical Garden (St. Louis) New York: Brooklyn Botanic Garden; Old Westbury Gardens; Planting Fields Arboretum (Oyster Bay) Ohio: Dawes Arboretum (Newark); Holden Arboretum (Kirtland); Spring Grove Cemetery and Arboretum (Cincinnati) Pennsylvania: Longwood Gardens (Kennett Square) Virginia: River Farm (Alexandria) Washington: Washington Park Arboretum (Seattle) Washington, D.C.: United States National Arboretum…

there’s nothing quite like pulling a crisp root vegetable from newly thawed ground and prepping it for the table in just a few minutes. Radishes, carrots, turnips and beets are cold-hardy staples that fill the gaps when little else grows. Because they are so versatile, they too easily become an ordinary refrain: the only roots we bother to grow. It turns out there are roots for every season, and growing them in succession with other crops can help loosen and renew soil. Spring heralds new growth, but as gardeners we know that successful crops begin in the off season. When summer’s main crops die back and cooler temperatures set in, we have time to reflect, amend soil and purchase seeds. Planning the next season’s garden creates a pact between us…

Sow. March and April are the busiest months for indoor seed starting. To produce healthy, compact seedlings, provide at least 16 hours of light each day. I use four-foot fluorescent grow lights hung on chains. This allows me to adjust the height of the lights as the plants grow, so they stay just a few inches above the tops of the seedlings. The result is strong, well-branched seedlings ready to be plugged into my garden. Plan. Don’t get overwhelmed by spring cleanup and garden prep. Instead, stay organized and keep on track by making a list of garden tasks, plans and projects. Prioritize those that can’t wait, like seed starting, and tackle the less pressing ones when you have time. Buy smart. Whether you need garden soil to fill a…

1. CORNELIAN-CHERRY DOGWOOD Cornus mas. This large shrub is a tough multiseason plant that blooms early in the spring with a profusion of small yellow flowers. Before blossoming, the unopened buds look like popcorn kernels. In summer, it develops red fruit that is enjoyed by birds. USDA Zones 4–8. 2. REDBUD Cercis canadensis. One of the most arresting trees at the edge of the woods while in bloom, redbud produces a flush of small, lilac-colored flowers up and down its stems before the leaves bud out. The summer leaves are heart shape, and in the fall they turn a translucent yellow. Zones 4–8. 3. SNOWDROP Galanthus nivalis. One of the earliest harbingers of spring, snowdrops poke small, white bell-shape flowers up through the melting snow. These bulbs will spread naturally…

What do garden designers consider when creating combinations of spring-blooming flower bulbs, perennials and flowering trees and shrubs? Beyond the basics, what criteria do they weigh to take a combo to a higher plane of beauty? How do they balance short-term delight with long-term efficiency? How do designers script their plant partnerships so that they’ll unfold sequentially, week after week, as winter morphs into spring and spring into summer? How do they accommodate bulb foliage’s die-back where naturalizing is a goal? How do they deal with foraging animals? The bulb experts at Colorblends thought it would be interesting to explore how some accomplished garden design professionals approach these questions. “We reached out to three designers whose work we admire and asked if they’d be willing to share the thinking behind…

Patricia Smyth, owner of Essence of the Tree, a mail-order Japanese maple nursery, specializes in growing woody plants in pots. Here’s her advice for choosing containers: Choosing a container that suits your garden will first depend on the size of your tree or shrub. For optimum health and root growth from a young plant, graduate pot size by doubling the volume of soil. That is, if you buy a tree in a one-gallon pot, choose a container that holds two or three gallons of soil. As the tree matures you’ll keep doubling the size of the container until the tree reaches the desired size. You can then use root pruning and reduction pruning to maintain its size and keep the tree in that same container. Find a container that is…

For many, pumpkins are associated with autumn’s sweet desserts and festivities. But these versatile fruits can provide interest in the vegetable garden all summer long, with a final reward of unique, homegrown ingredients for recipes or decoration. A STORIED CROP Pumpkins and other crops in the Cucurbitaceae family originated in Central America, where native people would roast and consume strips of pumpkin flesh or dry the skins and weave them into mats. When European colonists arrived in the Americas, they prepared a dish believed to be a precursor of modern pumpkin pie. They cut the top off the pumpkin, removed the seeds and filled the inside with milk, spices and honey before baking it over hot ashes. The popular tradition of pumpkin carving was derived from an Irish custom of…

“HI. I’M JOHNNY CASH.” An iconic salutation, and a perfect way to introduce yourself, especially if you are indeed Johnny Cash. But times have changed. Pop stars now call themselves things like H.E.R., 6LACK, and Lil Nas X. How do they introduce themselves in a hurry? Dunno. Likewise, in gardening, the days of ‘Raydon’s Favorite’ aster (Aster oblongifolius ‘Raydon’s Favorite’) are gone. Mostly, this a good thing. Although ‘Raydon’s Favorite’ is a great plant, I’m willing to bet that old man Raydon didn’t have a marketing degree and that the name never increased sales by even one. But how do you explain a modern handle like Spiraea japonica Double Play® Big Bang™ ‘Tracy’ USPP 21,588; CBR 4073? Let’s break it down. First, the binomial Latin, a plant’s “Cash, Johnny.” Spiraea…