Mild winter weather in New England is cause for celebration; a chance to get outdoors, an opportunity to imagine spring has arrived early. Fortunately, the natural world remains on track and, for the most part, locked in dormancy. There are, however, garden elements that really stand out during the long, cold winters here, regardless of whether the weather is bitter or tepid.
Rhododendrons, for example, are nature’s thermometers; the degree to which their leaves droop and curl is a measurement of how many layers are needed to venture outdoors. The arborvitae are helping keep deer populations alive — at least up to the point where they can reach the sprays of green foliage — all while the white pines stand as silent sentinels watching the wind and the birds breeze past. This week’s column will focus on outstanding and unusual evergreens and shrubs for winter interest and even winter blossoms.
New England weather poses challenges for evergreens to thrive; they must tolerate deep freezes, damp-to-wet and cold conditions, salt spray from the ocean or roadways, and the insatiable hunger of our deer populations. I have always considered evergreens to be the backbones of a good garden, anchoring the design with presence, texture, and patience. The colder months are when evergreens can shine, especially when they are carefully considered and well-sited.
Evergreens
I wish to introduce two evergreen conifers with beautiful forms and interesting foliage, which are generally uncommon in the region’s landscapes. Both hail from Japan and are generally slow growing.
Japanese Umbrella Pine (Sciadopitys verticillata)
This unique tree features whorls of dark-green, thick needles, with the terminal whorl on each branch resembling the spokes of a verdant umbrella, hence its name. The needles are large in comparison to our native pine trees and far thicker, almost succulent. Running your fingers through the foliage is a pleasant activity. I promise you will not get poked or scratched! The species grows to 70 to 90 feet in cultivation, although specimens in its native forests grow well over 100 feet. For reference, this species grows about 10 feet in a decade. The branches are quite flexible, though wet snow can cause some damage. A cultivar called “Joe Kozey” was developed with a slenderer habit and tighter branching, allowing it to withstand heavier snow loads. Another cultivar, “Green Star,” was developed to maintain its deep, lustrous green color over the winter months. It attains only 12 feet in height by 6 feet in width — I wouldn’t quite call this a dwarf conifer, but it’s a well-sized addition to any suburban garden. Lastly, the cultivar “Wintergreen,” a selection from Sydney Waxman at the University of Connecticut, provides a mid-tier option with excellent cold hardiness and a mature height of 20 feet by a width of 15 feet.
Sugi, also known as Japanese cedar or Japanese redwood (Cryptomeria japonica)
This tree is not a recent arrival to New England gardens, but an exceptionally versatile one with several excellent selections from the delightfully rounded dwarf “Globosa” and “Globosa Nana” selections to the stalwart “Yoshino” that grows upright and fast, reaching 30 to 40 feet in height. There are other selections worth researching for rock gardens and small spaces, as well as variegated and weeping forms.
Winter shrubs
Believe it or not, there are shrubs that can bloom in winter in New England. When we think of winter interest, the radiant stems of red, yellow twig, and silky dogwoods come to mind, or the spectacularly bright fruit of winterberry or beautyberry shrubs. But few think of flowers. The following two shrubs are unusual and may take some legwork to track down. As they are distinct, your garden will become that much more singular with the addition of one of these wonderful winter-blooming shrubs that buck the trend of flowering during the warmer seasons.
Wintersweet (Chimonanthus praecox)
This shrub is aptly named for its season of bloom and the fragrance that its pendant, bell-shaped, and pale yellow blooms produce during mild winter days. It is a deciduous shrub reaching 10 to 15 feet in height and 8 to 12 feet in width. The bloom time for us at the northern range of its hardiness is February to March. The naked stems produce gorgeous, soft yellow flowers with a maroon center, in singles or pairs, with a sweet fragrance. The selection “Luteum” lacks the maroon center, instead featuring a uniform yellow on the petals. This shrub benefits from a sheltered position and southern exposure, as well as being near doors, windows, and pathways where its delicious aroma can be wafted and enjoyed.
Spiketail (Stachyurus praecox)
This deciduous plant has pendant chains of urn-shaped flowers that bloom in late February into March. Though capable of withstanding lower temperatures down to 5 degrees, it benefits from a sheltered position where desiccating winter winds can have a reduced effect. The flowers appear on last year’s growth before the foliage emerges, so any pruning for health or shape should take place in the spring after blooming.
Ulrich Lorimer is the director of horticulture at the Native Plant Trust in Framingham. Send your gardening questions, along with your name/initials and hometown, to ulorimer@nativeplanttrust.org for possible publication. Some questions are edited for clarity.
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