Bring grace to the landscape with weeping trees
Trees and shrubs with weeping growth habits have fascinated people for centuries. Many of these species have a long history of cultivation, particularly in Europe, where some have been highly sought collectors' items.
But weeping plants are special characters, and their unique features require special consideration. Failure to take these into account can lead to disappointment. A weeping tree can become a major asset in the garden or a plant that looks oddly out of place.
Because of their unusual form, weeping plants tend to become focal points of a landscape whether that was the designer's intention or not. So you need to use weeping plants judiciously. Too many in a single vista will create a busy, chaotic feel in the landscape.
It's a personal thing Depending on their form, weeping plants elicit particular emotional responses from people. Some weeping types-such as Camperdown elm (Ulmus glabra 'Camperdownii')-make people feel somber or forlorn. These are plants we often find in cemeteries or old estate gardens.
Others are so strangely shaped, they seem like creatures from outer space. One of the weeping larches, Larix decidua 'Varied Directions', reminds people of Phyllis Diller on a particularly bad hair day. At The Morton Arboretum, we have a weeping blue spruce, Picea glauca 'Pendula', that could well have been a creation of Dr. Seuss. It almost always stops visitors in their tracks, and they contemplate it with furrowed brow. One plant book describes it as a "wet rag." Other books sing its praises.
Often, it's the larger species-the weeping beech, katsura and linden-that take our breath away with their graceful, cascading effect. The weeping silver linden, Tilia tomentosa 'Petiolaris', is a strikingly beautiful tree. (In some literature, this plant is listed as a separate species, Tilia petiolaris. Recent publications, however, consider this tree a selection of Tilia tomentosa.) The branches, laden with fragrant flowers and leaves with a silvery underside, cascade from a massive, rounded crown. It is used as a street tree in Rochester, N.Y., where its towering presence makes a majestic impact. So, when you're selecting a weeping plant, think about the impact you want it to have, and choose accordingly.
Give 'em room to grow Weeping plants need room to spread and "do their thing." If you place a weeping plant in a confined area, you may be creating an ongoing pruning and maintenance problem and ruin the natural form of the tree.
Young weeping plants often need staking to establish their form. Many weepers put out multiple leaders that sprawl along the ground. For best results, pick a central leader and stake it to create a more pleasing, upright form. You'll need to keep it staked until the trunk has developed a rigid structure.
Most weeping plants result from grafting the weeping cultivar onto a rootstock. Not only does this tend to make them more expensive; but it has the potential to create problems later. Therefore, when purchasing a weeping plant, carefully examine the graft union, making sure there is no cracking or irregular growth at the graft. The most effective grafts for weeping trees tend to be those made relatively high because this helps keep the weeping portions of the plant off the ground and allows a better upright form to develop.
So, what are some weeping plants we recommend? Here are a few favorites.
Coniferous weepers * Weeping Alaska cedar-Chamaecyparis nootkatensis 'Pendula'-USDA Zone 4 This tree, which grows 30 to 45 feet tall, is one of those rare weeping plants for narrow spaces. The weeping habit is created mostly by the branchlets, which turn up like little ski jumps (see photo, at right). 'Pendula' has intense dark-green foliage that creates a nice backdrop for showing off the fruits of deciduous hollies in winter. A native of coastal Alaska and the Pacific Northwest, this species performs best with abundant moisture and protection from drying winds.
* Weeping junipers >From a maintenance standpoint, the junipers can be a tough group with >which to work. Weeping Eastern red cedar, Juniperus virginiana 'Pendula', >has a nice pyramidal form with pendulous branchlets, but it is subject to >cedar-apple rust and bagworms.
Needle juniper, Juniperus rigida, has an elegant habit with a central leader, horizontal secondary branches and weeping branchlets, but its extremely sharp needles make it a hazard to work around.
Tolleson's weeping juniper, Juniperus scopulorum 'Tolleson's Weeping', has an interesting form. Its silver-blue foliage hangs string-like from arching branches. Unfortunately, this species is subject to Phomopsis blight and also serves as an alternate host for cedar-apple rust.
Nevertheless, many people employ these plants successfully in the landscape. If you desire the unique look of a weeping juniper, the maintenance drawbacks should not rule them out. Hardiness varies considerably according to species, but some weeping junipers are quite cold tolerant, succeeding even in Zone 3.
* Weeping white spruce-Picea glauca 'Pendula'-USDA Zone 2 This tree has a narrow, upright habit with highly pendulous branches. The clone that is now in the trade originated from The Morton Arboretum collections.
* Weeping Serbian spruce-Picea omorika 'Pendula'-USDA Zone 4 This is a beautiful, slender, pyramidal tree with slightly twisted branches. It prefers deep, rich, well-drained soil and protection from winter winds.
Deciduous weepers * Weeping katsura-Cercidiphyllum japonicum 'Pendulum'-USDA Zone 5 'Pendulum' is a fast-growing tree that creates a 15- to 25-foot-tall mound of gracefully weeping branches (see photo, at right). Its blue-green leaves bring to mind a waterfall. In autumn, the leaves range from yellow to apricot. Just as delightful as the color is the spicy cinnamon fragrance the leaves exude in fall. Katsuras appreciate ample moisture, especially while they're getting established, and rich, well-drained soil. Their best fall color may come from acidic soils, but they tolerate neutral or slightly alkaline soils.* Weeping European beech-Fagus sylvatica 'Pendula'-USDA Zone 5 With its huge arching canopy, the weeping beech looks like a sculpture (see photo, at right). The smooth, gray bark takes on an elephant-hide appearance in older trees. This handsome bark combined with the impressive weeping form gives this tree a striking winter aspect. Shimmering green leaves emerge in spring, turning a lustrous dark green in summer and rich russet and golden bronze in fall.
This cultivar has some variability in form. Sometimes the branches initially grow horizontally before turning down, creating a tent-like appearance. Other times, the tree may have a central leader from which the branches hang down, almost like arms. This is a slow-growing tree, but one that is definitely worth planting.
A purple-leaf form, Fagus sylvatica 'Purple Fountain', also is available.
* 'Louisa' weeping crabapple-Malus x 'Louisa'-USDA Zone 4 This is one of the nicest weeping flowering crabapples. In fact, it is simply gorgeous. A broadly weeping form, it grows 15 feet high and wide, and its branches turn up at the tips. It has red buds, pink flowers, yellow, persistent fruit, and glossy dark-green foliage. Plus, this flowering crab is highly rated for disease resistance.
* 'Chaparral' weeping mulberry-Morus alba 'Chaparral'-USDA Zone 4 In addition to its weeping form, one of the nicest aspects of this mulberry is that it doesn't bear fruit. Growing 10 to 15 feet tall over many years, with an equal or greater spread, it has bright-green leaves and is a tough plant that can succeed in urban sites. It is easier to use in the landscape than another weeping cultivar, 'Pendula', which has messy fruit and a gnarled, twisted (grotesque, some say) growth habit.
* Weeping Higan cherry-Prunus subhirtella 'Pendula'-USDA Zone 5 This fast-growing tree adds a graceful element to any landscape, in any season. The weeping gray-brown branches have prominent, horizontal lenticels, giving this tree an interesting winter appearance. In spring, the tree is covered with single, pink, half-inch flowers (see photo, at right). The fruits are red, maturing to shiny black. Higan cherries are among the most heat-, cold- and stress-tolerant of the cherries.
* Golden weeping willow-Salix alba 'Tristis'-USDA Zone 3 Weeping willows definitely have their place in the landscape. They're especially useful in wet sites where little else will grow. However, they have earned a poor reputation because of their messiness and their susceptibility to ice and wind damage, pests and diseases.
Fortunately, the availability of some relatively dependable types has allowed designers to retain weeping willows in their plant palette. 'Tristis' is one of the hardiest and most beautiful of the weeping types. It grows 50 to 70 feet tall and produces a canopy of golden, weeping branches.
Trees and shrubs with a weeping habit can create a strong emotional impact in the landscape. But use them appropriately. Choose specimens carefully, site them properly and, if necessary, stake them while they're young to establish a pleasing form. Used excessively or carelessly, they can create a chaotic jumble. Used judiciously, they create striking focal points, magnificent specimens and a source of wonder.
Tim Boland is Curator of Horticultural Collections at The Morton Arboretum, a 1,700-acre outdoor museum in Lisle, Ill. Patrice Peltier is a Chicago-based freelance writer and staff member of The Morton Arboretum.
Some weeping plants have distinctive habits that create a whimsical effect in the landscape. Three popular choices are:
* Weeping European larch-Larix decidua 'Pendula'-USDA Zone 2 This tree's weeping branches and soft green needles create a graceful landscape specimen. Its winter appearance is coarse and reveals an umbrella-shaped canopy after needle drop. These trees can attain a large size over time.
* Weeping Norway spruce-Picea abies 'Inversa'-USDA Zone 2 This popular cultivar has pendulous branches and a dense habit.
* Weeping Eastern white pine-Pinus strobus 'Pendula'-USDA Zone 3 With its long branches that sweep the ground, this is one of the most popular weeping plants for the landscape (see photo, at right). A large specimen at The Morton Arboretum always draws attention with its graceful, pendant habit and distinct horizontal form. Old specimens can attain heights of 20 feet with an equal or greater spread.
One way to learn more about trees and shrubs with weeping habits is to see them in the landscape. This can be especially useful for determining how much space a particular tree needs, as well as what emotional impact it might have.
Public gardens and arboreta are good places to see these special trees and shrubs. For example, The Morton Arboretum, a 1,700-acre outdoor museum of trees and shrubs in Lisle, Ill., has more than 30 kinds of weeping plants, offering ample opportunity to learn about how to use and maintain these plants in the landscape. Other gardens and arboreta maintain similar collections.
Contact the American Association of Botanical Gardens and Arboreta (AAGBA-Kennett Square, Pa.) for information about facilities in your area. You can reach the AABGA by calling (610) 925-2500, or try its website at www.aabga.org.
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