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. 

Asters in New England

Another thing besides beautiful foliage that New England has in the fall is an abundance of native asters. In the Massachusetts County Checklist there are 27 species of Aster indigenous to Massachusetts. (Technically speaking, however, there are no more New World asters, they have been reclassified into a number of new genera including Doellingeria, Eurybia, Ionactis, and Symphyotrichum.)  A few of these native species, such as the purple New England Aster (Symphyotrichum novae-angliae) and Bushy Aster (S. dumosum) have become common in many gardens with cultivars such as ‘Alma Potschke’ and ‘Wood’s Purple’.  I would like to call attention to some commercially less common species that I have purposely grown or that have appeared around my house.

One of my favorites, which I have grown from seed is the Smooth Aster, Symphyotrichum laeve. This is a medium tall aster that grows in full to part sun and relatively dry soils. Its stems are strong enough that it does not always needed to be staked. However like many asters cutting back by 1/3 at the end of June gives a stronger, bushier plant. The flowers are usually a lavender blue measuring over 1” wide. In this photo are some freely seeded plants that show some variation in flower color. These are most commonly commercially available as the ‘Bluebird’ cultivar.

The Big-leaf Aster, Eurybia macrophylla, is early blooming and grows well in dry shade. My plants started blooming in late June and did not start going to seed until early September. Here we see the fuzzy seed heads and a few residual blooms. This species will spread by both seed and rhizomes. It forms dense mounds of foliage and can be used as a ground cover.  And It's still not bad looking when the seed heads replace the flowers.

Another shade tolerant species is the White Wood Aster, Eurybia divaricata. This species also grows in dry shade, e.g. upland woods. It blooming period is later than for the big leaf aster and it can be a vigorous spreader. This photo was taken at Mount Auburn Cemetery, but they are quite common in the woods in New England.

Two species that grow like weeds around my house are Heart-leaved Aster and Arrow-leaved Aster, Symphyotrichum cordifolium and S. urophyllum, respectively. Structurally these two asters are very similar. The most obvious difference is that the flowers of Heart-leaf asters tend toward blue-violet shades, while the Arrow-leaved asters are whiter.

In the garden they form clouds of light colored flowers that stand out against darker colored foliage.

I purchased the Heart-leaved aster thinking it would combine well with my yellow cone flowers (Rudbeckia), but the cone flowers are just passing as the aster begins to open up in mid-September. I need to find a later blooming yellow for this combination to work, such as the annual Black-eyed Susan (Rudbeckia hirta), or a late blooming Goldenrod like the ‘Fireworks’ cultivar (Solidage rugosa ‘Fireworks’). The Arrow-leaved aster just blew onto my property on its own.

 

The last aster that I have been working with is the Smooth Violet Prairie Aster (S. turbinellum). This aster is not native to New England, rather its home is in the Plains States. I got this plant for use in a parking lot island, where it gets no extra watering or special care, 4 years ago and it is still going strong. It has profuse blue-violet blooms from September to October on relatively stiff stems. The only care I give this plant is to cut it back by 1/3-1/2 in late June to keep it from getting too tall and flopping over.

 

My first preference was to use the Smooth Aster (a New England Native) on this site, but that plant was not available at the time of installation. I had only a single pot of Smooth Aster to put in at the time.  While it is still surviving there, the Prairie Aster is really doing well in that location (and the bees love it, too).

Last Blooms of the Year

Over 7 months ago I was writing about all of the Witchhazels that were in bloom and how they were among the first plants to bloom in the new year.  Well, Common Witchhazel, Hamamelis virginiana, is among the last of the native shrubs to bloom.  Sometimes you don't notice the flowers because the leaves are still attached.  My 3 year old witchhazel began blooming about 10 days ago (early October) while the leaves were still quite green.  Now bloom is peaking and the leaves are turning chartreuse and yellow.

These photos are of some older plants at Mount Auburn Cemetery.  Leaf drop is underway and the flowers are becoming a more prominent feature of the plant.  If you get close you can smell the distinctive witchhazel scent; although it as not as strong as for the hybrid, H. x intermedia, and Vernal Witchhazels, H. vernalis.















In this close-up you can see the 'wart' on the leaf that is actually a gall caused by the witch hazel aphid (Hormaphis hamamelidis).  There are some stories that link the name of the plant to resemblance of these galls to the imagined warts on a witch's nose.

A Weekend in Mid-Coast Maine

My wife and I are fortunate enough to have a friend who invites us up to their cottage in Mid-coast Maine at the end of the summer. For the botanist in me, this is a native plant wonderland, especially since I am more used to seeing invasives and exotics in my suburban landscape habitat. I would love to have this kind of native plant diversity around my home.

  

Most of the easily identified plants were late summer and fall blooming species; however I could pick out some early bloomers, like bluebead, Clintonia borealis. Up around the cottage and the nearby woods I found a variety of goldenrods, including silverrod, and asters and drifts of hairy Solomon’s seal, wintergreen, sweetfern, and maple-leaved viburnum.

One goldenrod I particularly like is the Blue-stemmed Goldenrod, Solidago caesia, since it grows well in shady locations – a good way to add some brightness to an otherwise dark location.

Mixed in with the Viburnum were seedlings of striped maple, Acer pensylvanicum, which has similarly shaped leaves, but they are about 4 times larger.

 

Along the gravel access road I spotted some indian cucumber root, Medeola virginiana, which I think is more striking in fruit than when it is actually in bloom. The plant shown is about 18" tall.  Also along the road were masses of witchhazel, Hamamelis virginiana, which I had never noticed before. This is probably due to my learning more about what plants look like, than would be the sudden appearance of full-sized shrubs. Witchhazel is one of the latest blooming native shrubs, here it is mid-September and the flowers were just beginning to open. In colder climates these shrubs bloom while the foliage is still attached, in warmer places the flowers may persist until after leaf drop.

A little deeper in the woods I identified a new plant for me, round-leaved dogwood, Cornus rugosa. At first I though it was another viburnum, since it had opposite pairs of leaves, but the leaves were decidedly un-toothed, so I dug a little deeper into the field guides. This looks like it could be a nice understory shrub to grow in the shade under pines.

Next to the pond near the cottage there are thickets of winterberry holly, meadowsweet and maleberry (Lyonia ligustrina). It took me a long time to ‘key out’ the maleberry, since I had never seen it before. This shrub grows in moist and sandy places and has flowers similar to blueberries. I originally had it as different shrub, leatherleaf, but some things about the description in the guide just didn’t seem right, particularly the dried flower clusters. So I kept at it using some other guides. It is ‘dangerous’ to use just one key or a limited set of observations when identifying unfamiliar plants on your own. If you are conflicted about a plant ID, you may have it wrong. This process can be tedious, but going through the details helps me remember the plant better than just reading what it is on a tag.



Popham State Park

We also made a trip to the beautiful sandy beach at Popham State Park, not far from Bath, ME. Of course I went in search of wildflowers. Here you see the aptly named seaside goldenrod (Solidago sempervirens) growing right out to the edge of the rocks. I also found some stunted New England Aster (Symphyotrichum novae-angliae) growing on the rocks a little closer to land.

'Cottage Garden'

Back at the cottage, there is some room among all these wild native plants for a small ‘cottage garden’. I was told that it took all summer for these sunflowers to reach maturity, growing from seed, but they made it none the less. Every time I visit here I learn some new native plants. Maybe next year I will grab my fern guide and venture a little deeper into the woods to see what’s growing there.

Wildflower Meadow in September

I paid another visit to the Mount Auburn Cemetery Wildflower Meadow last week and I was floored by the intensity of the blooming.  While it is still a little early for the asters to get going there was a ton of late summer plants going full tilt.  One of my sentimental favorites is the Browneyed Susan, Rudbeckia triloba.  This is a biennial or short lived perennial.  The first year here there were only a few plants in bloom.  This year there were more than a dozen big healthy plants in full bloom. 

Other species shown in this photo are the New England Blazing Star, Liatris scariosa var. novaeangliae, Showy Goldenrod, Solidago speciosa (a showy but aggressive species), and the white, cloud-like Hyssop-leaved Boneset, Eupatorium hyssopifolium.  You can also see traces of some long blooming Shrubby Cinquefoil, Potentilla fruticosa, off to the left.  Among the grasses that are showing off their seed heads are Little Bluestem and Side-oats Grama (foreground).

In a nearby area the Pink Turtlehead, Chelone lyonii, is blooming.  This species is native to a small area of the Southeast, but these are 'escaped' populations also found in the Northeast, from New York to Maine.  White Turtlehead, Chelone glabra, on the other hand, has a much wider native distribution throughout the eastern US.

Forked Bluecurls Close-up

Some other natives that are blooming in the area have also jumped to my attention.  On a recent plant survey a native annual, Forked Bluecurls, Trichostema dichotomum, was blooming profusely on an otherwise dry hilltop in the Boston suburbs.  It stood out as as a rather lush little plant (6-8") with deep blue flowers amongst the dried leaves and grasses.  Its native habitat is on dry or sandy soils of upland woods and old fields.  While some sources indicate it prefers part to full shade, these plants were growing in nearly full sun rooted at the fringes of rocky outcrops where moss and eroded stones collect.  Looking carefully at the blow up, you can see the curly forked stamen that gives this plant its common name.

The last plant to mention this week is the Bearded Beggarticks, Bidens aristosa var. mutica.  After watching this annual grow taller and taller for 3 months (now about 6' tall), it has finally burst into bloom.  These plants are coming back from seed produced from the crop I planted in 2008.  Right now it looks great and the bees love it, but I do question its position in the garden.  This plant is probably better positioned to the back of a border where it forms a green curtain for the first part of summer before it begins its month of bloom in early September.  It also produces a whole lot of viable seed, so if you hate garden 'editing', this may not be the plant for you.

It's not Poison Ivy

As I was surveying which native species were growing successfully under my Norway Maple (for a future blog post), I came across many seedlings with ‘leaves of three.’ I thought, #Golly#, Poison Ivy! On closer examination, I realized that these were growing as individual plants, not a vine and the leaf shape, with its entire, unlobed margins, just wasn’t quite right for poison ivy. After checking some field guides and looking for similar plants growing in the area, I found out that these were seedlings of Wafer Ash, Ptelea trifoliata. The parent plant was growing behind the garage in an area I rarely paid any attention to.

Wafer Ash, also known as Hop Tree or Stinking Ash, is native to the Southeastern and Midwestern States, its native range does not extend up to Massachusetts, but it is listed as hardy to zone 5A.  I’m not sure how this tree got into my yard.  It’s not commonly used in the landscape trade and with a name like ‘Stinking Ash’ it’s not likely to be popular.  This name refers to the musky odor of its bark and leaves when crushed.  In this case, the name is a bit deceiving; I find that, while not pleasant, it does not smell as bad as something like wild Black Cherry.
Wafer Ash grows as a large shrub or small understory tree with irregular branching, usually growing to about 20 feet in height. The seedlings put down a tap root that can make them difficult to pull up.  It is native to dry rocky uplands and is very tolerant of shade. These two features make it suitable for growing under a Norway Maple, with its dense network of thirsty roots and dense shade canopy. Wafer Ash prefers neutral soils and is listed as deer highly resistant and tolerant of salt and ‘mine spoils’. The only conditions it does not tolerate are soil compaction and flooding.

This tree blooms in early to mid-June in the Boston area with terminal clusters of yellow-green, sweet smelling flowers. (Some sources list flower scent as unpleasant, but I found it quite nice and detectable several yards away.) The tree serves as a larval host for Eastern Tiger Swallowtail and Giant Swallowtail butterflies and is generally attractive to birds and pollinating insects. For more photos and information check out this link to the Wildflower Center.

The name ‘Hop Tree’ refers to its use in earlier times as a hop substitute in the brewing of beer. The dried seed pods (samara) can be decorative. My experience under the Maple and elsewhere in my yard is that these seeds high viability and offspring can appear just about anywhere. I don’t know if their spread is a result of being blown around naturally or from being caught up and thrown around by the lawn mower.

In my experience, the Wafer Ash is an excellent North American native understory tree with high wildlife value for dry, shady conditions. While it not commonly available in the landscape trade, there are a few commercial sources. Lacking that, I’ve got a bunch growing in my backyard. (You can reach me through the Adams Garden fan page on Facebook.)