With a new planting season approaching I am planning on
continuing my crusade to replace the
invasive species with native, mostly indigenous, plants. I have another round of brush clearing to do
this winter, especially the removal of some Autumn Olive tree/shrubs. I am also looking to reduce the number of
Butterfly bushes and Forsythia on the property and replace them with higher value native shrubs.
Over Christmas I took the time to finish reading Designing Gardens with Flora of the American East, by Carolyn Summers. The chapter on 'showy substitutes for invasive
plants' was very inspirational in making up my plant list for this season. This book is an excellent resource for anyone
interested in designing native plant gardens.
There is sound reasoning behind each of the recommendations in this
book. I found this to be much more useful than just a list of what
should or should not be done when designing a garden or landscape. To
enhance the wildlife value of our property I am trying to use a combination of plants that have
something in bloom throughout the season for the pollinators as well as berries
and fruits for the birds and small mammals.
Anyway, here's a list of my target plants for 2014:
Pussy Willow, Salix discolor. I was surprised that this is a native
species. I is used so commonly in early
spring decor that I figured it had to be imported. The catkins swell in very early spring, first
as white, silky buds, then opening to reveal either yellow (male) or greenish
(female) flowers. Pussy Willows are
dioecous, male and female flowers are borne on separate plants. My plan is to use the pussy willows as
replacements for Forsythia. The color
intensity will be much less, but the wildlife value will be so much higher with
the willow. For all its flowers, I have
seen very few bees visiting a forsythia in bloom. Pussy
Willows like full to part sun and prefer moist soils but will tolerate some
dryness. They are larval hosts for Viceroy and Mourning Cloak butterflies and they tolerate deer.
I took this photo of a shrubby willow at the Arnold Arboretum
about 5 years ago. I did not record the
name at the time. As I was trying to
find out more info about it, I went to the arboretum's web site and found that
they have actually made an Internet accessible map of their plantings. Using that map and my memory of where I
took the photo, the willow in question is either the native Bebb's Willow, S. bebbiana, or an
introduced Black Willow, S. gracilistyla 'Melanostachys'. Based on the light color of the catkins, I guess
that it's the former.
Another substitute for Forsythia is Spicebush, Lindera
benzoin. Its flowers impart a yellow
haze to the forest understory about the same time as the Forsythia are in
bloom. It grows better in shadier
situations than either Pussy Willow or Forsythia.
For a partly shady area I would like to try replacing the Forsythia with Red Osier Dogwood, Cornus sericea. This plant is in bloom from mid-late May and
follows up with nutritious berries in mid-late summer. Besides the flowers and fruits this dogwood
also has purplish fall foliage and red-colored stems in winter, features
definitely lacking in the one-trick pony, Forsythia. Species plants can get large (6-10') but
there are compact cultivars like 'Isanti' and 'Arctic Fire'. A big problem with dogwood is that deer find
most of the plant pretty tasty, but I have seen large plantings doing well
along the roadsides. This dogwood serves as the larval host for the Spring Azure butterfly.
This 'Isanti' cultivar is in full bloom at the end of May and should grow to about 6 feet. Cutting back the older growth each year will keep the size down and give more new red stems in the winter. |
As far as replacing the Butterfly Bushes, Buddleia davidii,
a multi-shrub approach may be needed.
Butterfly Bush has a long period of bloom and is very attractive to
pollinators. But it's like candy. The plant does not act as a host for any native insects. Thus, as it displaces native species, it
excludes useful host plants, and degrades the habitat value of the garden.
The seed heads of Sumac make them easy to spot. Not sure which species this is. The stems of R. glabra are smooth, while those of R. typhina are hairy. |
For the second part
of the season I will put in some American Elder, Sambucas nigra ssp. canadensis
(often S. canadensis). American Elder
likes medium to moist soils and part to full sunshine. I have seen this growing in roadside ditches
covered with white umbels in the middle
of summer. Dark, palatable berries
follow in early fall. This shrub does
not have a neat compact form, but neither do most forms of Butterfly Bush. I am somewhat concerned about deer browsing
on the young plants, so some protection will be needed.
This native Spiraea blooms throughout the summer and is a magnet for bees. |
Other shrubs that provide mid and late summer flowers which I put in last year include dense St. John's Wort, Hypericum densiflorum, and Meadowsweet, Spiraea alba var. latifolia (this one blooms all summer long).
In the areas where I have cut down the Autumn Olive,
Elaeagnus umbellata, I am looking for native plants to provide lots of
mid-summer flowers, a large crop of
fruits, and fairly dense branching to provide cover for birds. Cockspur Hawthorn, Crataegus crus-galli,
looks to be a good fit. It blooms
through mid-June and has lots of berries from late summer into winter. It has dense horizontal branching and long
thorn that provide a lot of protection for birds. (For use closer to people there is a naturally thornless
variety, var. inermis.)
I would also consider Chokecherry, Prunus virginiana, while
blooming earlier, it is faster growing and has fewer disease problems. Chokecherry lacks the thorns of Hawthorn, but
can form a thicket-like colony. Looking
in Douglas Tallamy's book Bringing Nature Home,
the cherries are near the top of the list as far as their ability to
support butterfly species. Hawthorns
come in 12th, both way ahead of an invasive species like Elaeagnus.
'Blue Muffin' is noted for it's sapphire berries, as long as there is another Arrowwood around for pollination. |