This week on our Around the Grounds blog, we monitor some plummeting temps to see how well our native Rhododendrons fare. How adaptable are they really? You might be surprised!
continue readingWinter’s Green
Recently in Around the Grounds, we featured native shrubs that add splashes of color to the winter landscape. (Read our Winterberry and Red Osier Dogwood posts here.) While brilliant berries and colorful bark are important for winter interest, evergreen shrubs are the backbone of the garden, providing structure throughout the year. And, as we remind ourselves, green is a color, too!
Unfortunately, our suburban landscapes tend to use a very limited repertoire of evergreen plants. We think there are better and more interesting choices than boxwood and taxus for residential foundation plantings. Take a look at some of the evergreens we’ve used at the Nature Center:
One of our favorites is the native Inkberry (Ilex glabra). Inkberry resembles boxwood, with similar dark green, shiny leaves. And, like boxwood, it can be pruned into a hedge, or a sphere, or any shape Edward Scissorhands might fancy. We prefer to let it take a natural, rounded shape with dense branches as hiding places for songbirds.
Unlike boxwood, Inkberry is adapted to our climate because it is native here. Boxwood originated in southern Europe, northern Africa, and western Asia; all climates very different from ours. Gardeners here are advised to wrap boxwood with burlap in winter to protect it from cold, wind, and salt – not a great look for “winter interest.”
Inkberry is not only cold-tolerant, even to temps below zero, but it enjoys our acidic soil and doesn’t mind sitting in water after heavy rainfalls. It is deer-resistant and salt-tolerant. It does prefer full sun, but can handle some shade. The straight species will get 6 to 8 feet tall, but it can be sheared and shorter cultivars are available.
We’re not sure why so many suburban dwellers like plants pruned into ball shapes, but we do know a native evergreen that will take that shape without any help! Growers have developed cultivars of our native Arborvitae that grow naturally into a ball shape without pruning.
Arborvitae (Thuja occidentalis), also known as Eastern or Northern White Cedar, is very familiar as a tree; often used as a hedge or screen. It is native to our region and has wildlife value as a nesting site and seed supply for birds. Be advised that it is also famously attractive to deer. Some sellers of Globe Arborvitae claim the shrub is more deer-resistant than the tree, but we planted it close to a busy patio just in case. There are numerous cultivars of Globe Arborvitae available, with varying maximum sizes and slight color variations. Because we always prefer native plants, we would choose this little shrub over either boxwood or taxus – and we don’t have to prune it!
Another delightful evergreen shrub developed from a native tree is Pinus strobus ‘Soft Touch’ or Dwarf Eastern White Pine. ‘Soft Touch’ makes a great foundation plant. It is slow-growing, eventually taking a flattened shape no more than 2 feet tall, and wider than it is tall. It stays a lovely bright green all winter long. Its needles really are soft to the touch, and it’s hard to resist giving it a pat every now and then.
At the entrance to the Nature Center, we use another dwarf evergreen as a container plant. Dwarf Alberta Spruce (Picea glauca ‘Conica’) also was developed from a very large native tree, the White Spruce. This dwarf variety is very slow-growing and maintains its classic Christmas tree shape without pruning. It can live for years in containers, but should eventually be given some space in the landscape. It can become a 10-13 foot tree in time, so we will have to turn ours loose on the grounds in a few more years.
This blog is authored weekly by Cathy Ludden, conservationist and native plant educator; and Board Member, Greenburgh Nature Center. Follow Cathy on Instagram for more photos and gardening tips @cathyludden.
Winter Interest that Pays Dividends
On a cold gray winter day, when the leaves are gone and the last flower is just a memory, finding some bright color in the landscape is a blessing. Discovering “winter interest” in a great native shrub that also provides food and shelter for birds and pollinators is a win-win.
In our last two blog posts, we suggested Winterberry and American Holly with their bright berries to perk up winter views. Here is another of our winter favorites:
Cornus sericea, commonly called Red Osier Dogwood or Red Twig Dogwood, is a great native shrub that should find a place in the landscape just for its brilliant red bark in winter. But it’s also beautiful the rest of the year – a true four-season plant. In mid-spring, it blooms with flat sprays of fragrant white flowers. All summer, it forms a rounded shape topping out at 6 to 8 feet tall and wide.
In late summer, pretty white berries form to feed the birds. In fall, the leaves turn varying shades of red and purple and begin to drop from the lower branches first, revealing the characteristic red bark. As the shrub matures, you can cut back the older woody stems in spring to encourage new sprouts to come up in vibrant red for the winter show.
Red Osier Dogwood has a wide native range in the United States. It grows on river banks and in wet areas throughout the northern part of the country. It’s a great choice for rain gardens or any sunny area where water collects, especially if you want a low-maintenance natural thicket. Red Osier Dogwood will send out suckers, or shoots, that will root themselves and form new plants to fill in an area. It is an ideal choice for controlling erosion or steep banks in areas that tend to flood. But it will also grow in average garden soil and can easily be controlled by cutting off suckers as they appear.
And you couldn’t find a better bird habitat! Red Osier Dogwood provides nesting sites, berries for food, and a supply of caterpillars for baby birds. Like other dogwood species, it is a host plant for the beautiful little Spring Azure butterfly.
So, all these features are dividends for nature while we enjoy the winter interest in our landscape. That’s a pretty good investment!
This blog is authored weekly by Cathy Ludden, local expert and advocate for native plants; and Board Member, Greenburgh Nature Center. Follow Cathy on Instagram for more photos and gardening tips @cathyludden.
‘Tis the Season to be Holly
Holly has been associated with winter holidays since long before Christmas celebrations began. It is thought that ancient Romans decorated with holly for Saturnalia, the winter feast in honor of Saturn. Druids and Celts believed the plant had magical powers because while all other trees lost their leaves, the holly not only stayed green, but displayed brilliant red berries in the darkest days of winter. So, holly branches have been cut and used for winter decorations for thousands of years. Our seasonal color scheme of red and green no doubt originated with holly.
How fortunate that European settlers in the American colonies found a new species of their favorite winter plant growing here! American holly (Ilex opaca) differs from European holly in subtle ways and it can be difficult to tell them apart. The leaves of the American holly are not as shiny as the European variety, and the berries are often single rather than in clusters.
American holly trees typically grow 15 to 40 feet tall and 8 to 15 feet wide, but they can reach 60 feet where they are happy. They prefer well-drained, moist, acidic soil, and full sun for best berry production. Like other hollies, they are dioecious with male and female flowers on separate plants. For best fruiting, a male tree should be within 50 feet or so of the female.
American holly is well-adapted to our area, of course, because it evolved here over thousands of years. It is less vulnerable to winter winds than many of the European varieties and it enjoys our acidic soil. It is a care-free evergreen and makes an effective year-round privacy screen. In a mixed evergreen border with Rhododendron maximum, White pine, and native junipers, it is not only attractive, but provides food and safe nesting habitat for birds.
And when the winter holidays are here? What better combo than White pine, Winterberry, and American holly for the cheeriest “winter interest” in the neighborhood?
We think that’s just jolly!
This blog is authored weekly by Cathy Ludden, local expert and advocate for native plants; and Board Member, Greenburgh Nature Center. Follow Cathy on Instagram for more photos and gardening tips @cathyludden.
Deck the Halls…and Gardens
Every landscape needs “winter interest,” and several of our favorite native shrubs are real show-offs this time of year.
Without a doubt, the star of the season is Winterberry (Ilex verticillata). Winterberry is a holly, but unlike most hollies, it is deciduous – meaning it loses its leaves in the fall. And that’s a good thing! The berries start turning red in October while the leaves are still green. Weeks later, the leaves drop off revealing brilliant clusters of berries that remain all winter.
Or, at least, the berries could remain all winter unless the local birds have other ideas. We assumed for a long time that the berries needed all winter to ripen, because neither rain nor snow nor dark of night caused them to disappear until robins returned in the spring.
But in some years, mockingbirds, blue jays, and cardinals seem to celebrate the holidays with Winterberry snacks. So, we can’t totally promise the berries will remain all winter. But the robins definitely will finish up whatever is left in the spring.
If you have a boggy area on your property, Winterberry is a great choice – it will live in standing water and will happily send out shoots to form a thicket. So, it’s a great choice for a rain garden or a problem wet area. It does well in average garden soil as well, with full sun and regular moisture, and can be controlled easily by removing new shoots.
Like other hollies, Winterberry is dioecious, meaning both male and female plants are necessary for berry production. Bees visit the flowers on the male plant and carry the pollen to the flowers on the female plants to fertilize the ova and produce berries. Your local nursery will sell you a male shrub to plant somewhere near the female so bees can find both plants when they bloom in the spring. The flowers are small and white and not very noticeable, but the shrub is a lovely deep green all summer long.
Winterberry can grow 8 to 12 feet tall, but can be pruned for shape and size. There are cultivars that naturally stay much smaller – ‘Red Sprite’ takes a rounded shape and stays 3 to 4 feet tall. You’ll need ‘Jim Dandy,’ the male pollinating plant, to get berries on ‘Red Sprite.’ We suggest avoiding the recently-introduced Asian hybrids of Winterberry. The value of their berries for native birds and the risk of them becoming invasive are unknown.
This time of year, you may find whole branches of Winterberry mysteriously disappearing when it’s time to decorate for the holidays. The Garden Club of Irvington recently collected Winterberry and other foraged materials from our grounds to decorate the Nature Center. The impact of Winterberry on our fireplace mantles is spectacular! (Word of caution: the berries can be toxic to dogs, cats, and toddlers, so it’s best to keep them out of reach.)
Winter solstice is nigh, and the Winterberry is bright!
This blog is authored weekly by Cathy Ludden, local expert and advocate for native plants; and Board Member, Greenburgh Nature Center. Follow Cathy on Instagram for more photos and gardening tips @cathyludden.