Native Plant Wish List for 2014

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'm not sure of the exact species.  This photo is from the end of March in Boston.

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 early part of the summer I am looking to Smooth Sumac, Rhus glabra.  This is also a common roadside plant, but not so common in the nursery trade.  It's chartreuse panicles do not stand out to humans, but they do to butterflies.  What is most noticeable in this shrub is the scarlet fall foliage and the deep red berries through the fall and winter.  It grows to about 15 feet, similar to many of the mature butterfly bushes around here. The larvae of the Hairstreak butterfly use Sumac as host plants.

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.

The other shrub that I will be putting in place of the olives is Arrowwood Viburnum, Viburnum dentatum.   These bloom in late May through mid-June and produce dark blue berries from late summer through autumn.  As I have mentioned before in this blog, Viburnums are self-sterile, so you need to have more than one genetic individual of each species to get berries.  Fortunately a local nursery is offering seed grown, wild-type plants so I won't have to worry about self incompatibility.  Wild-type Viburnums can get too large for many landscaping situations.  There are a number of more compact cultivars for garden use, such as the 'Blue Muffin' (aka 'Christom') shown here.  Together the Viburnums and the Hawthorn or Chokecherry will provide a nice edge habitat for with both food and shelter for wildlife.

Native Plants Update 2011

Now that most of the fall chores are done, I took some time to think about how some of my native plants were doing. My main focus is on those that I started from seed, but I have also put in some newer perennials and shrubs that put in as more mature specimens

New this Year from Seed

I successfully started the following species from seed this year.

• Pearly Everlasting, Anaphalis margaritacea, is a perennial, similar to the annual sweet everlastings (Pseudognaphallium obtusifolium) that I have had trouble transplanting into the garden in the past. These germinated well, but did not do well in ‘regular’ soil; however the ones that I put into a bed of decomposed bark chips seem to be taking hold. So it appears that these plants like a well drained, airy soil.

• Flowering Spurge, Euphorbia corollata, had limited germination but did grow well in the soilless mix. The transplants, like the Anaphalis above, showed a strong preference for lighter, well drained soils.

• Crowned Beggarticks, Bidens coronata, were difficult to germinate, unlike some of its prolific cousins. They did mature and bloom early in the season (June-August), but after setting seed this annual expired. This is in contrast to the Swamp Beggarticks that spend the summer growing to a good sized shrub before blooming in September.

It's nearly December and this plant has been trying to
bloom for awhile.  The arrow shows one of the trilobed
leaves for which this species is named.

• The woodland sunflower, Helianthus divaricatus, also had limited germination, but produced fairly strong plants. Like the Brown-eyed Susans, these have spent their first year in the ground getting established. These have a reputation for being aggressive, so they have been put under the Norway Maple.

• Brown-eyed Susan, Rudbeckia triloba, was difficult to germinate in moist sand. I did get better results with cold stratification in damp soil for 2 months in the refrigerator. These seedlings are spending their first year getting established in the soil, i.e., no flowers this year. Although with the extended warm weather this year there are a couple which have been trying to bloom since October.

Old from Seed

The following plants have performed well from seed in the past and I just wanted more of them:

• I really love the Orange Hummingbird Mint, Agastache aurantica ‘Navaho Sunset’, as much for the smell of its foliage as I do for the flowers. This perennial grows well from seed under lights and blooms the first year. Older plants are maturing to 2-2.5’ tall. So far I have not seen strong evidence of self seeding, but I believe it should.

Two shades of Sulfur Cosmos with
some American Bellflower in the back.

• Sulfur Cosmos, Cosmos sulphureus, are southwestern natives that grow and reseed well in garden soil in the Northeast. I had grown these in the past, but they were pushed out by my experiments with the more massive Bidens aristosa. I do prefer these in the garden since they are of more manageable size and have beautiful bright flowers. While they are fine left on their own, they do better, bloom-wise, with dead heading.

• Rock Harlequin, Corydalis sempervirens, is a favorite of mine, though, like many other natives this is not for general garden soil. It likes lean, well drained conditions. Some that I had growing in a pot, bloomed and started a second generation in an adjoining tray. I’m over-wintering these seedlings for next year. Once these plant have set a lot of seed they tend to peter out and die.

• The Indian Blanket, Gallardia pulchella, seeds that I got in Austin three years ago are still viable (refrigerator storage). These seeds produce variable plants that that will stand tall in the open or grow sideways to find an opening in more competitive environments. So far I have seen no evidence of self seeding in my New England garden, though the plants themselves need a good hard frost to kill them for the year.

• Cucumberleaf Sunflower, Helianthus debilis, is a Southeastern native that has made its way up the east coast as far as Maine. I got the cultivar ‘Pan’ three years ago and it seems to be coming back true to seed.

• Spotted Beebalm, Monarda punctata, is a short-lived perennial that is easy to start under lights and grows well in a variety of soils. After three years I am beginning to see signs of it spreading, just as the older plants are beginning to die off.

• I also bought the Texas native Drummond Phlox, Phlox drummondii, seeds in Austin three years back. Seeds stored in the refrigerator are still viable, and they will reseed themselves within a season, but I have not seen any overwinter up here naturally.



Purchased Native ‘Annuals’

This year I tried using all southwestern natives in my deck flower boxes. Just to be bold I went with a ‘primary’ color scheme: Mealy-cup Sage, Saliva farinacea, provided the blue spikes; I used Apache Beggarticks, Bidens ferulifolia, for yellow ‘fillers’ and the Drummond Phlox for a deep red, that I hoped would act as a ‘trailer’. I purchased the Sage and Bidens at a garden center and the phlox were from seed. While these plants survived the hot and occasionally very dry conditions, I found that the effect was compromised by ‘spotty’ blooming. The Salvia was a constant blue, but the Bidens tended to bloom in cycles that rarely coincided with the Phlox.

The Phlox is blooming while the yellow Bidens is between bloom cycles.

Returning on their Own

I have a fairly long list of annuals, biennials and perennials that are spreading mostly by seed. In managing these I need to be willing to toss out the extras (that I can’t give away) rather than let one or two aggressive species dominate. So here’s a quick summary of this years results:

• Red Columbine, Aquilegia canadensis reseeds well and stays ‘close to home’.

• Swamp Marigold, Bidens aristosa, vigorous self-seeder, but not too hard to pull out.

• American Bellflower, Campanulastrum americanum, also a vigorous self-seeder, but grows in dry shady locations.

• Strawberry Blite, Chenopodium capitatum, thought this was lost but it reappeared; this plant is too ‘sloppy’ for the flower garden, but it has other uses.

• Philadelphia Fleabane, Erigeron philadelphicus, mostly coming up from self-scattered seed in the lawn.

• Northern Sea Oats, Chasmanthium latifolium, was grown from seed started about 5 years ago and up until last year had been staying put. This past season I was finding it scattered around the garden. I have been moving the extra to underneath the Norway Maple, where this enthusiastic growth is needed.

• Sand Love Grass, Eragrotis trichodies, grows on dryish, sites with full sun. It produces attractive seed heads in early fall and slightly taller than it’s relative Purple Love Grass. This is a relatively short lived grass, so a decent seed bank will be needed to ensure its continued presence.

• Biennial Beeblossom, Gaura biennis has been reseeding itself since I first planted it in 2008. Even with cutting back in the early summer, this biennial will reach 6’ tall.

• American Pennyroyal, Hedeoma pulegiodes, has been reseeding itself consistently since 2008. It tends to concentrate in pavement cracks. When possible I have been moving this to more useful garden locations.

Scarlet, or Texas Sage

• Black-eyed Susan, Rudbeckia hirta, tends to stay close to the original planting location. My plants typically survive from 1-3 years.

• Scarlet Sage, Salvia coccinea, has been a surprise. It has reseeded itself in a variety of locations and matured on its own to give healthy, blooming specimens from July through September. Based on my experience with other red Salvias, I did not expect this one to come back so strongly.

• Showy Goldenrod, Solidago speciosa, spreads by both seed and underground runners. I have had to remove excess plants from the garden and am running out of places to put them.

• Swamp Verbena, Verbena hastata, is also an aggressive self-seeder. It grows in pavement cracks as well as in the garden.



New Perennials & Shrubs

In addition to the plants originally grown from seed, I put in the following perennials and shrubs. In the sun:

• Butterfly Weed, Asclepias tuberosa, is a tap-rooted perennial. It is found in coastal areas, so I am hoping that it will tolerate a roadside planting location.

• Sheep Laurel, Kalmia angustifolia, is a spreading shrub, growing to about 3’. I’m putting in place of some Meadowsweet that had grown too large.

Fall color of 'Blue Muffin' Viburnum
(a crimson colored leaf from a 'Winterthur'
Viburnum is to the back left).

In the shadier areas I added Canada Anemone, Anemone canadensis, Celandine Poppy, Stylophorum dipyllum, and Blue Stemmed Goldenrod, Solidago caesia. The Poppy and Goldenrod have performed well in the shade. The Anemone seemed to disappear after a month or so, but I could still find a leaf or two late in the season.

Finally, I added an Arrowwood Viburnum, Viburnum dentatum ‘Blue Muffin’, to the shrub border. Mainly I wanted to see how this oft used cultivar performs. So far my specimen stayed green longer than my 'Winterthur' Viburnum and, when the leaves did change, the coloration was fine, but not spectacular; a good foil for showier plants.

So, now I can start thinking about next year.  More on that later....

Getting Viburnums to bear Fruit

Last year I posted a blog on how using cloned plants may reduce the viability of seed produced in the garden. In some cases this is not a bad thing from a design point of view, if it is desirable to limit the number of ‘spontaneous’ seedlings and maintain a 'clean' ground plane. If your goal is to produce seeds and berries for wildlife, then the use of sterile, or self-sterile plants is of no advantage. The situation that brought this up was that the Viburnum nudum ‘Winterthur’ that I have has never produced more than a couple of small berries each year. After 5 years of this I investigated the situation and leaned that in order for Viburnums to produce seed it must be pollinated by a genetically distinct individual. (You see most cultivars are clones of the same individual.)  So last summer I picked up a straight species form of Viburnum nudum and planted it nearby.

These pale green berries will turn pink, then dark blue as they ripen.

This year I’ve got many, many more berries forming on the ‘Winterthur’, as well as the species plant. The species and ‘Winterthur’ bloomed at the same time; this is very important for cross-pollination. There is a difference in form and fall color between the two plants. ‘Winterthur’ is more upright and the fall colors on a single plant vary from light orange to red. The species plant is more lax and turn a rich burgundy color in the fall. Now I’m looking forward to seeing some of those brightly colored berries later in the fall.

Fall color for 'Winterthur' cultivar

Viburnum nudum species in early November.



Only a few of the signature blue berries
matured on this lone Arrowwood Viburnum.



Earlier this year I also added an Arrowwood Viburnum, Viburnum dentatum ‘Christom’= Blue Muffin®, to fill a gap in a shrub border. To my knowledge there are no other Arrowwoods in the neighborhood. This species of viburnum blooms 3-4 weeks earlier than the ‘Winterthur’ and only two clusters of late blooms overlapped with the opening of the flowers on the ‘Winterthur’. On inspection today, the Arrowwood has just a few mature berries on the plant, all of the other flowers just fell off shortly after blooming. So it may be that the pollen from these two species is compatible, but their blooming times are so different that they are not practical mates.

In any case, now when I recommend Viburnums in a wildlife-friendly garden, I try to include two different cultivars of the same species, or look to see if there are some other plants of the same species growing nearby. I will need to look for a chart with bloom times for all of the Viburnums to see if there any other possibilities for interspecies compatibility, as is done with Holly.