Native Seeds for 2011

After assessing what did and did not do well last year, I placed my seed orders for native seeds. Here’s a run down on what I’ll be trying this year.

New Plants
Pearly Everlasting (Anaphalis margaritacea) A perennial with white, long lasting flowers. I’ve been frustrated growing the related annual Sweet Everlasting (see below), so I thought I would try a perennial version.

Butterfly Weed (Asclepias tuberosa) This perennial that does well in dryer sunny locations and attracts many pollinators. I’ve seen a few plants commercially available but I wanted to make sure I had some growing this year.

Rosey Sedge (Carex rosea) I was given a small clump of this foot-tall perennial grass for nearly 5 years ago. I thought I should test it out in some different locations. This sedge prefers part to full shade.

Flowering Spurge (Euphorbia corollata) This perennial is also known as Prairie Baby’s Breath. I thought this could be good for general landscape use, with white flowers through mid-summer.

Woodland Sunflower (Helianthus divaricatus) This perennial sunflower grows well in dry shade. It can be weedy in the garden, but I really want to test it out under the Norway Maple. I’ve seen this brightening up shady oak woodlands in the middle of summer.  This is the first year that I have been able to find seed.


Repeats
Alleghany vine (Adlumia fungosa) I’ve written a lot about this biennial vine. I just can’t get enough. Note that these seeds need 90 days of cold stratification, so don’t wait if you want to try this one!

Orange Hummingbird Mint (Agastache aurantica ‘Navaho Sunset’) grew quite well last year and now I need more to try with clients. I really like the scent of the gray-green foliage and the flowers are pretty nice, too.

Rock Harlequin (Corydalis sempervirens) This another plant that I love.  I just need more rocky places to put it.

Sulfur Cosmos (Cosmos sulphureus) This native of Mexico (a part of North America) grows as an annual in the Northeast.  I had a crop that returned for 4-5 years until it got crowded out by some Bidens. I thought I would try to start it up again. While the bloom is similar to that of the swamp marigold (B. aristosa), this Cosmos starts blooming earlier and for a longer time.  Also, the foliage is not as dense.

American Pennyroyal (Hedeoma pulegioides) has been getting established from a planting 2 years ago, but I’d like to try more in some different locations. This will do well along a path.

Spotted Beebalm (Monarda punctata) was pretty successful last year and I need more to try with some clients.

Sweet Everlasting (Pseudognaphalium obtusifolium) has given me trouble on transplanting in the past two years. I’ll try this again, this time seeding directly in the garden in prepared soil (not in compacted turf).

One last try...
These three plants did not germinate for me last year, but I’ll try one more time with a lengthy stratification in moist starter mix.

Fern-leaf False Foxglove (Aureolaria peduculata) This biennial is parasitic on oaks, but, reportedly, does not need them for germination. I also have some of these scattered around a nearby oak. Stay tuned…

Tall Swamp Marigold (Bidens coronata) is an annual, with good-sized yellow flowers. I'm curious to see how if differs from the other Bidens I have around.

Brown-eyed Susan (Rudbeckia triloba) is a short-lived perennial, that while taller, has a more delicate appearance than the typical Black-eyed Susan (R. hirta).  I've posted a number of photos of this species over the past year.

Returning on their own:
I'm sure the Swamp Marigold (Bidens aristosa) will be back, but I will be pulling these up to make room for new plants.  I will have a lot of the biennial American Bellflower (Campanulastrum americanum) in 2011, judging by the large number of rosettes in the 2010 garden.  Also, I will keep an eye out for the return of any of the Texas native annuals: Indian Blanket (Gallardia pulchella), Drummond Phlox (Phlox dummondii) and Scarlet Sage (Salvia coccinea), that bloomed so nicely last year.

Upcoming Conferences in the New England Area

'Tis the season for landscaping conferences and meetings.  Before we get too busy with the physical work, the wintertime is a time to do some learning and meet others who are doing similar work, as well as seeing what new plants and products are out there. 

The following is a listing of some of the conferences happening in the New England area over the next 3 months.  There may be others, but these are the ones that have crossed my desk recently. 

22nd Annual Landscape Design Symposium on January 20th and 21st, 2011, titled: Uncharted Territory: An Expansive Approach to Environmental Landscape Design.  This series of symposia was developed by Larry Weaner, one of the top people in the area of naturalistic design and the use of native species in the landscape.  This 2-day event features 11 speakers covering a range of topics including history, plant selection, sustainable practices and natural landscape design.  The conference is held at Connecticut College in New London, CT.

For the landscape professional you can't beat the 3-day long New England Grows, from Feb 2-4, 2011 at the new Boston Convention and Exposition Center.  This is a huge show featuring both landscape equipment and supplies, plant materials, and consulting services.  In addition there are a series of talks covering a wide range of landscape industry topics.

Natural Landscape Design: Meadows & Woods, Feb 16-18th, at Tower Hill Botanic Garden in Boylston, MA, is another Larry Weaner sponsored course.  This is focused on the landscape design professional who wants to learn more about the natural design process and management of a naturalistic design, especially in the context of Meadows and/or Woods. 

The ELA  (Ecological Landscaping Association) conference is March 3, 2011.  This one day conference is focused on using ecological methods in the landscape and is accessible to anyone interested in improving the ecological functioning of their landscape.  In addition to a very good line up of speakers, there is a marketplace where you can see many new products and speak with the vendors.  This conference is in Springfield, MA, so you can connect with people outside the Boston area.  This was the very first landscaping conference I attended 6 years ago, and I have been there every year since.

2010 Flower Show

And finally there is the New England Spring Flower Show, March 16-20, 2011, at the Seaport World Trade Center in Boston.  This event is sponsored in part by the Massachusetts Horticultural Society.  This year the theme is "A Burst of Color: Celebrating the Container Garden".  Program detail do not appear to be available yet, but the topic of container gardening should be well suited to the Flower Show format.  Last year I saw some crazy items and got some good ideas. 

Check out the links for more information about each of these meetings.  Except for the Tower Hill course, I am planning to attend all of these events.  People ask me 'what do you do in the off-season', I tell them I attend conferences and get juiced-up for the spring.  What are some other meetings that should not be missed this winter?

Native Annual Seeds that I tested in 2010

As I get ready to order seeds for 2011, I’m looking back on the native annuals and biennials that I tried out last year.  Some were successful and bear repeating while others went nowhere.  Some of the failures were not surprising while others just wouldn’t germinate and I’m not sure why.  So here’s a review of last years seeds.

Native to Massachusetts:

Adlumia fungosa (Allegheny vine, biennial) I got a few more plants from seed I collected in 2009.  Even better, I saw several plants coming up on their own from the previous season’s plants! 

Aureolaria pedicularia (Fernleaf yellow false foxglove, annual)  None of these germinated.  Since these plants are partially parasitic on oaks, my seed starting mix may not have been right, or they may not have been conditioned properly.

Bidens coronata (Crowned beggar’s ticks, annual)  Very few of these seeds germinated and those few that did failed to mature.  This was a surprise to me since other Bidens species tend to run wild in the garden.  I’ll give this one another try, directly in the garden.

Corydalis sempervirens (Rock harlequin, short-lived perennial)  These had good germination and transplanted well. I really love this plant.  I’ll need to find more places with thin rocky soil for this plant.

Hedeoma pulegiodes (American pennyroyal, annual) sprouted freely in the garden near where I had planted seedlings in 2009 – even under the Norway Maple.  While I couldn’t see them all, I could detect their aromatic aroma whenever I stepped on or mowed over them in the lawn.  It is reported that these plants act as an insect repellant when rubbed on the skin.  I hope to give that a try this year. 

Neither the Hypoxis hirsuta (Eastern yellow star grass, perennial) nor the Polygala sanguinia (Purple milkwort, annual) seeds germinated for me this year.  I will give up on these two for now, also I have run out of seed. 

Pseudognaphalium obtusifolium (Sweet everlasting, annual)  These seeds germinate well, but the transplants do not mature well in the yard or in pots.  Its native habitat is in depleted soils with little competition from other plants. However, I was surprised to find one out of the lawn, near the one successful plant from 2009.  I’ll try these again with direct seeding in a prepared area. 


Native to New England:

Monarda punctata (Spotted bee balm, biennial) germinated and transplanted well.  It also bloomed quickly and was a big hit with the bees and some very interesting wasps in the garden.  Since this Monarda prefers drier conditions, I have a roadside spot that would benefit from this plant that I would like to try it in this year.

Rudbeckia triloba (Brown-eyed Susan, biennial) failed to germinate for me.  The germination conditions on the packet were fairly complex, especially when compared to relative Rubeckia hirta (Black-eyed Susan) which germinates freely after a month of cold moist stratification.  A small population of R. triloba is getting established at the Wildflower Meadow at Mount Auburn Cemetery in Cambridge, MA.





For plants Native to other parts of North America I found the following:

Salvia, Spotted Beebalm, Agastache and Gallardia
all mixed together in my South-facing bed.

Agastache aurantiaca ‘Navaho Sunset’ (Golden hyssop, perennial)  This cultivar germinated reasonably well and while it was a little slow to get started growing in the garden, it was up to full size and blooming by mid-July, producing a cloud of orangy-pink flowers.  The foliage also smells really good when disturbed. We’ll see how well these overwinter/reseed.  I’ll be growing more of these this year!

Cleome serrulata (Rocky Mountain Bee Plant, annual) again failed to sprout for me, either indoors or out. I can get the seeds to germinate, but not develop into seedlings.  Again, there may be something wrong with my starter mix or the newly germinated seed may be too delicate to sow into the growing mix.  In either case, I think I need to move on. 

Eschscholzia californica (California poppy, annual/tender perennial) germinates well in the garden, but my site is a bit too cool to allow many of them to reach maturity.  I usually get only a handful of blooms each year. This plant also shuts down when it gets too hot.  While I loved this plant in my native California, I think it is time to move on from this one too.

Euphorbia marginata ‘Summer Icicle’ (Snow-on-the-Mountain, annual) is a tap rotted annual and is reported not to transplant well.  So after soaking the seeds in warm water for a few hours these were planted directly in the ground in early June.  When mature they provided foot-tall mounds of white foliage and flowers.  This cultivar is shorter than the species (1-3’). 

Gallardia pulchella (Annual blanket flower, annual)  These seeds came from the Wildflower Center in Austin, TX.  These germinated and transplanted well after 30 days of cold stratification (may not have been necessary).  This species has a laxer form than the commercial cultivars, but it bloomed well both in pots and in the garden where it intermingled with the Spotted Beebalm and the Agastache.  This plant was very popular with the bees. I allowed the flowers to go to seed so we’ll see if they are still viable in the spring. 

Helianthus debilis ‘Pan’ (Beach sunflower, annual) reseeded itself into the same pot from last year.  This is not too surprising since there are naturalized populations of this Texas native scattered along the Eastern seaboard up to the Northeast.  This second generation had the same upright branching form of its parent.

Phacelia tanacetifolia (Lacy phacelia, annual) germinated very well and grew well in potting soil, but did not take well to being transplanted.  It has been recommended as a cover crop, with the warning not to let it go to seed in agricultural fields.  I may try this again as a direct sow plant.

Phlox drummundii (Drummond phlox – straight species, annual) also came from the Wildflower Center. These seeds germinated and transplanted well.  The flowers were true to the species scarlet red, but there was some variation in flower shape.  While I am not too hopeful that about the seeds overwintering outside, I did get a second generation late in the summer.  Relative to other flowers in my Massachusetts garden, these flowers were not very attractive to the pollinating insects.

This petal shape, with the white edging,
was unique from the other plants I had this year

Salvia coccinea (Texas sage, annual/tender perennial) is another Texas native.  Seeds for this plant germinated and transplanted well.  It grew equally well in a pots and in the garden bed and was very attractive to the bees.  Based on the native range of this species I don’t expect that any of the seeds would overwinter in my garden.

If you have any advice for growing the plants I listed here, I love to hear it.  What new native plants are you thinking about trying for next year?

Under the Norway Maple

One of the most common trees in the residential setting is the Norway Maple, Acer platanoides. It was first introduced into the United State in 1756 by John Bartram. It is well adapted to the climate in the Northeast and grows well under a wide range of growing conditions, making it a preferred tree in urban and suburban landscapes. It’s tolerance of for almost any environmental condition, ability to grow in the shade, prolific seed production and overuse in the landscape has led to this becoming a dangerously invasive species in the Northeastern US.

Working in residential landscapes I often encounter the difficulty of working around this species. Its dense shade and greedy roots that suck moisture out of soil make it difficult to underplant. While many consider the Norway Maple as allelopathic (producing compounds that retard the growth of other plants), there are studies that indicate that this is not the case. (One study found no experimentally measurable allelopathic effects from Norway Maple.)  I think the problems encountered under a Norway maple are mainly due to the shade it casts and the dense network of roots that scavenge moisture and nutrients from the soil.

Norway Maple stump 6 years after a native species
restoration at Mount Auburn Cemetery

This photo shows the best method for dealing with a Norway Maple. Despite my disdain for this tree, I have not taken that step on my own property, yet. Since there is not another tree in the area to provide shade around the house for the hot afternoon sun I am hesitant to open up the canopy that much. Instead I have been exploring which native plants will grow under its canopy.

To get some ideas, I tried to learn about what grows the natural forest community along with Norway Maple in its native range (Europe and Asia). I thought I could find native equivalents to those European species. This tree is naturally found in mesic deciduous forests and mature riparian communities. While I did not find a definitive description of the other plants in this community (I’m sure that information is out there) I did get some clues from a site on the Plant Formations in the Central European BioProvince.  One shocking conclusion jumped out.

Many of the perennials and shrubs that grow in forests along with the Norway Maple are also invasive, or have tendencies toward invasiveness, in North American forests. These include goutweed (Aegopodium podagraria), fig buttercup (Ficaria verna), Tartan honeysuckle (Lonicera tartarica also L. xylosteum), yellow archangel (Lamium galeobdolon), and lily-of the valley (Convallaria majalis).  So I would be hesitant to recommend any new non-native species with the possibility of making a bad situation worse. However there were some others that are better behaved such as sweet woodruff (Galium odoratum), European ginger (Asarum europaeum), Siberian squill (Scilla sibrica), Tartan dogwood (Cornus alba) and fumewort (Corydalis solida) and some really neat plants like common hazel, Corylus avellana (from which comes ‘Harry Lauder’s Walking Stick’ ). 

In my own testing, I have been selecting native plant species that are tolerant of dry shade. So far I have found a number of natives that survive but do not flourish. It seems to be a general trend that all plants grow smaller and slower in that environment. However, there are a few that are more than holding there own. My plant list is as follows:


 

Smooth Aster and Showy Goldenrod,
both about 1/2 size of those
in other parts of the garden

Spreading:

American Bellflower (Campanulastrum americanum), American Pennyroyal (Hedeoma pulegioides), Smooth Aster (Symphyotrichum laeve), Heartleaf Aster (Symphyotrichum cordifolium), Virginia Creeper (Parthenocissus quinquefolia), Wafer Ash (Ptelea trifoliata) , Wild Bleeding Heart (Dicentra eximia), Witchhazel (Hamamelis virginiana ).

Holding their own:

Male Fern, still green after a couple of frosts.



Male Fern (Dryopteris filix-mas), Christmas Fern (Polystichum acrostichoides), Rosey sedge (Carex rosea), Alumroot (Heuchera villosa), Barren Strawberry (Waldsteinia fragariodes), Hairy solomon’s seal (Polygonatum pubescens), Largeflower bellwort (Uvularia grandiflora), Rosinweed (Silphium integrifolium), Showy Goldenrod (Solidago speciosa), Twinleaf (Jeffersonia diphylla), and Possumhaw Viburnum (Viburnum nudum).  This particular Viburnum was selected to improve pollination of the 'Winterthur' Viburnums nearby.

Promising, but still early:

Allegheny vine (Adlumia fungosa), Black Huckleberry (Gaylussacia baccata), Black-eyed Susan (Rudbeckia hirta), Inland Sea Oats (Chasmanthium latifolium), Lowbush Blueberry (Vaccinium angustifolia), and Pennsylvania sedge (Carex pensylvanica).

Failures, faded away or died outright:

Canada Mayflower (Maianthemum canadense), Fetterbush (Leucothoe fontanesiana), Foamflower (Tiarella cordifolia), Green and Gold (Chrysogonum virginianum), and Squirrel Corn (Dicentra canadensis). (When I moved the Leucothoe to a different shady location, without the root competition, it perked up after a couple of weeks.)

Plants that should work, planned for next season:

Labrador violet (Viola labradorica) and Maple-leaf viburnum (Viburnum acerifolium),

In addition to using plants that are strong competitors that can get their share of moisture there are some maintenance practices that will help the understory plants. Limbing up and thinning the canopy to let in more sunlight has helped a lot. Also, new plants should be irrigated deeply to get them established as well as under droughty conditions (mid-summer). Returning leaf mulch to the understory area helps to build the soil.



I’d like to hear what other natives have worked for you under Norway Maples, or ones that have failed desperately.

Mistaken Identity

 

Oops, both are actually Meadowsweet



On looking back on an older post from May 2010, I realized that I had misidentified a native Spiraea.  While I had initially planted both Meadowsweet and Steeplebush in this spot, only the Meadowsweet had survived.  This became evident while visiting my sister last week.  I had given her a couple of pots of Steeplebush that I had grown from seed last year because she has a moister site, preferred by that particular species.

In this photo of Steeplebush, Spiraea tomentosa, gone to seed, you can see the the tight, upright flower plumes (typically pink to purple) and the deeply veined leaves, indicative to that species.  While I think it would be happier growing out in a moister area of the yard (growing to 4' tall), it appears to have a very nice form growing in a pot.  Maybe this is another 'Natives in Pots' candidate.  I'll have to see if I still have some leftover seed.

Meadowsweet, Spiraea alba, on the other hand has looser flower panicles (white to pale pink) and the leaves are not as deeply veined.  The specific variety I have, Var. latifolia, is native to drier upland sites, which explains how well adapted it is to growing around my house.  Mine bloomed continuously from early June until October and was a favorite of the bees.

It just goes to show, no matter how badly you want to have a plant, sometimes it just isn't there.

Berries and Bark at Tower Hill

I just attended the annual 'Trees in the Urban Landscape Symposium' at Tower Hill Botanic Garden in Boylsten, MA, yesterday.  It was a beautiful (but windy) day at a beautiful location.  I'll talk about the symposium in a later post, but for now I'd like to show you the site.  If you haven't been there recently, or at all, they have just opened a new Winter Garden and Limonia, which are great places to visit as the weather turns cold.


View of the Farmhouse across the Lawn Garden at Tower Hill

The last part of the symposium was a walking tour of these new areas and their Lawn Garden by Joann Vieira, Horticulture Director, Tower Hill Botanic Garden and Executive Director, John W. Trexler.  Most of the leaves are gone from the trees and deciduous shrubs to reveal some of the highlights of the plantings.

Beautyberry with Paper Birch and Winterberry Holly

This scene was really lit up by the afternoon sun, with the native Paper Birch and Winterberry Holly, Ilex verticillata, in the background and Purple Beautyberry, Callicarpa dichotomata, up front.  The bright red berries of the Ilex are very popular with the birds, especially later in the season, while the non-native beautyberry is less favored, providing more visual interest than wildlife value. 

Another striking planting with a lot of winter interest was this cluster of 3 Paperbark Maples, Acer griseum, surrounding a mass of 'Brower's Beauty' Pieris.  Some other interesting plants in this garden include some of the most luxurious Japanese Plum Yew, Cephalotaxus harringtonia 'Prostrata', and Siberian cypress, Microbiota decussata, that I have ever seen. Alas, no photos of these.  These two plants do show some resistance to deer browsing, a problem in this area.  There was also a large Boxwood, Buxus sempervirens ‘Newport Blue’, at 5-6’ tall and wide that seems to be doing quite well at this zone 5 location. There was also a native Inkberry, Ilex glauca f. leucocarpa, that had white berries and a form more like the species than a compact cultivar.  These berries do show up much better than the black berries that are normal to this species.

Winter Garden at Tower HIll

The new Winter Garden was designed to hold as much interest when viewed from the inside of the building as it is close up outside.  This row of Bloodtwig Dogwoods, Cornus sanguinea 'Midwinter Fire', really shows well as the leaves are lost and will not interfere with longer views across the garden, even as they grow taller.  This garden features a lot of low growing and other 'specialty' conifers. 

Leucothoe fontanesiana 'Scarletta'

One of the native plants used here is a low growing cultivar of Fetterbush, Leucothoe fontanesiana 'Scarletta'.  When protected from winter winds this plant is expected to grow 18-24" tall and have the scarlet tinged foliage in spring and fall.  I find this a much more appealing plant than the 'Girard's Rainbow' cultivar, that is common in the trade. 

 
 
 
So far my visits to Tower Hill have been limited to the Urban Tree Symposia in the fall, but I will need to make the 45 min drive from Boston in spring or summer so that I can appreciate more of what this garden has to offer.  Tower Hill Botanic Garden is currently open Mon-Tue,Thu-Sun 10am-5pm and Wed 10am-8pm.

Making good use of all those leaves

Well we've had a pretty nice fall foliage season in New England this year, despite all the dire predictions that our unusually hot and dry summer would play havoc with foliage season.  The inevitable end to foliage season is leaves on the ground that need to be cleared away.  I've always hated the idea of buying bags to stuff with leaves in order to throw them away.  That's kind of like throwing away money, isn't it. 

A few years ago the maintenance staff at Mount Auburn Cemetery began a practice of mowing leaves directly into the lawns rather than picking them all up and transporting them to a compost yard.  When you consider that leaves contain most of the minerals that the roots have taken out of the soil, returning those minerals to the ground essentially supplies the trees with the raw materials they need to produce a new crop the following year. 

Pros for mowing in leaves:

• No raking
• No leaf bags
• Relatively fast
• No transporting leaves for disposal
• Free fertilizer, may skip lawn and tree fertilization
• Naturally builds soil organic content 
• No special equipment (just a mulching mower)

Cons:

• Some leaf dust and scraps remaining
• Need to make an extra pass with lawn mower
• Dry leaves are abrasive toward lawn mower blades
• Some leaves, like walnut, contain compounds that retard growth of other plants

Since I've learned about that practice, I've been using it at home for the past two seasons.  This year my goal is that I will dispose of no leaves off of my property.  The following images show before and after shots of mowing the leaves into the lawn.  This job took me about 15 min, while raking and bagging would have taken at least an hour.  If the grass was a little taller or I hadn't waited so long between mowings, most of the debris would have disappeared immediately.  Also, since I have been doing this I have reduced the fertilization of the lawn to a single treatment with slow release fertilizer in the spring.  (I'm not a turf expert, but this works for me.)

 

For the leaves in the shrub beds, I'll rake and/or blow them out then run the leaves through a chipper which reduces the volume about 5 fold.  These leaves I'll save for a month or two then use them as a mulch on the garden and perennial beds. 

Some more ideas about how to treat fallen leaves and their benefits can be found at this link to Ecosystem Gardening.