Monday, March 29, 2010

2010 Boston Flower and Garden Show

After a one year lay-off the flower show has returned to Boston. I attended only one day of this 5 day event (March 24-28) and I was generally pleased with what I saw. For me the new venue, the Seaport World Trade Center was an improvement over the previous site. Most notably for me was the improved lighting which allows the display gardens look more ‘natural’.

Another change for this year was that the vendors and the garden displays were in the same area. This provided a nice, balanced mix of things to see. The competitive horticulture displays were located in a separate area which allowed for more intimate viewing.

Judging by the crowds there on a weekday, the show was successful. I heard from a friend that Saturday’s crowd was huge. So it sounds like the show was a success from an attendance point of view.

While the overall lighting was better than in the former location, I found that the use of tinted lighting over some of the garden displays was a disaster. For example, some display used blue-green tints on the arborvitae and reddish lighting on the rhododendrons. I could not tell what the plants actually looked like when the colors are rigged to ‘enhance’ them.

I was only there one day (Friday) and I found the lectures and demonstrations to be quite good. A few take away gems are:
Edible Landscaping with Paul Split, who talked about incorporating many conventional herbs in the landscape in unconventional ways. He also touched on companion planting and using plants to control pests. Some of his great ideas included using a ring of hostas (dense root mass) to control the spread of mints in a bed; use leeks to slow the spread of underground insects and pennyroyal to block insects crawling on the surface of the ground.

Listening to the landscape: Using Nature’s Cues to Design a Garden that Works by Scott LeFleur of the New England Wildflower Society. The key point I took away was that if you select plants that are right for the conditions on your site (light, water, soil conditions, etc.) then you do not need to add any additional materials, like fertilizers and soil amendments or extra water, to have a successful planting. Another comment was that it is best not to put debris from invasive plants into your compost pile, in this case, landfilling or burning is the better option.

The most energetic presentation of the day came from Kathleen Gagan of Peony’s Envy with her Passion for Peonies. This talk was full of excellent information on peonies, both herbaceous and tree types, and I took two pages of notes. There is a ton of information on the company website and I won’t recount much of it here. The only point I will share here is that some tree peonies are grafted onto the roots of herbaceous plants and that it is critical that these be planted deeply with the graft union about 6” underground. This will keep the rootstock from putting up new growth. Non-grafted tree types should be planted about 2” below ground level.

Most unique vendor I saw was Designer Palms Inc.  They make and sell steel palm trees many with lighted coconuts. At first I was aghast, but then, when I considered them as garden or poolside sculptures, they began to grow on me. In the right setting these could be a really unique accent or focal point in a garden where you want a tropical feel.

Next week it’s back to Native Plants!

Monday, March 22, 2010

What’s Blooming around Home

It’s still too early for a lot of spring flowers in the Boston area, but the great weather (after the recent flooding) this weekend got me out to look at the garden a little more closely. Most of the visual excitement is around the naturalized, non-native bulbs like Chionodoxa, Scilla and crocus. I was pleased to see how many bees were visiting what I believe to be these white Chionodoxa. (I am a little uncertain here because of the blue anthers – anyone have an alternate ID for this plant? It would be much appreciated.)  For next year I think I will try for more native spring flowers like Bloodroot, Dog-tooth violets and the Camas Lily, Camassia quamash.

These white flowers pictured above are actually Scilla mischtschenkoana, White or Early Squill.

While not open yet, the male catkins of my Sweet Fern (Comptonia peregrina) are getting plumper and have become noticeable. Also the hairs on the reddish branches really catch the afternoon light and make them glow.

Another sign of spring is when the Yews release tons of yellow pollen. This is the first year that I have really looked closely at the flowers. I noticed a difference between the flowers of two of my (unknown) cultivars. Also now is a good time to do some structural pruning on these to let more light in and stimulate some growth on the interior.

 What I am most pleased about seeing was the return of what I believe to be a Spring Blue-Eyed Mary from some seed that I had sown 2 years ago. I’ll keep a close watch on this seedling and let you know what it grows into.

Another pleasant surprise was a clump of Strawberry Spinach (Chenopodium capitatum) that overwintered. Normally this is considered to be an annual, but this plant did not mature last year, so I expect that it will finish out its lifecycle this year with some bright red berries. Check out the link for a seed source and more information on this native.

One thing I have noticed with some of the native annuals that I have tested is that those that do not flower and seed the first year will over-winter to complete their life cycle the following year.

Monday, March 15, 2010

"The Wild Garden"

A new edition of William Robinson’s 1870’s classic The Wild Garden has been published recently by Timber Press with additional material from Rick Darke. I was reminded of this by an essay by Darke appearing in the Jan/Feb issue of the American Gardener  entiled "What is Wild."  (Check out the link to the essay to see what I'm talking about.)  As I read this article I was immediately impressed at how well it captured my feelings on how I  like to design a residential garden—how to wed wildness and civilization.

 Robinson, a botanist and master gardener of 19th century Great Britain, wrote The Wild Garden in response to the contrived nature of the Victorian style garden. He was looking for a more natural, spontaneous, and lower maintenance way of gardening. The Wild Garden is not a manual on creating a wilderness, but rather a way of bringing nature and natural processes closer to the human environment. The key to this approach is to use plants that can naturalize to the existing site conditions and allowing them to grow and reproduce in a natural way to fill all the gaps or niches in the garden. Filling the ground plane with plants is naturally weed suppressive, conserves soil moisture and provides habitat for all sorts of creatures. To do this, plants need to be able to produce and disperse viable seed. Depending on the species this may require a genetically diverse ‘breeding stock’ and leaving some seed heads to mature and disperse their seeds.

In this style garden maintenance becomes more of an exercise in editing out seedlings rather than weeding and replacement of failed plants. The edited seedlings can become new additions to other areas or gifts to gardening friends.

In Robinson’s England of the mid 19th century, plants from the world over were available, including many from North America. These are reflected in the plant lists which he provided for the many different garden conditions encountered by the British gardener. His criteria for plant selection were that the plant be well adapted to an area to survive (rather than adapting the garden conditions to a few plants) and reproduce without dominating the garden (non-invasive). Early editions were focused on the use of introduced plant species while the 5th edition includes a significant chapter (60 pp) on ‘British Wildflowers and Trees.’ Thanks to ‘Google Books’ some of these early editions are available free of charge over the internet: 2nd edition; 5th edition.

This ‘wild garden’ approach is similar to that used for an entry garden I installed 3 years ago at the church I attend. This is a mixture of about half eastern US natives and half ‘exotics’. (I'm still waiting on a Leucothoe to fill the back corner.)  You can see that the ground plane is full. This garden gets no added fertilizer and very little supplemental water beyond the rain. Maintenance takes only 1-2 hours/year and mainly involves pulling out seedlings of bittersweet and euonymus from under the eaves where the birds sit. The Wild Bleeding Heart (Dicentra eximia) are spreading by seed and may be due for some ‘editing’ this year.

Monday, March 8, 2010

Spring is getting closer

Here in Boston we’ve had 3 days in a row in the 50’s and more warm weather ahead. Now I am starting to think seriously about spring.  In this area the first plants to bloom are the Witch Hazels.  These have actually been in bloom for awhile and are pretty much at peak now (first week of March).  Especially noticeable are the Asian hybrids like the pure yellow ‘Arnold Promise’ and the copper-hued ‘Jelena’ (Hamamelis x intermedia).  Once I got to know the subtlety sweet fragrance, I can tell that one is nearby before I could spot it.

The Chinese Witch Hazel (H. mollis) is also at full bloom right now. It can be identified by its more linear golden yellow petals. It also has a tendency to hold onto its old leaves, as shown here.

Since I’m a ‘Native Plants’ guy I have to mention our two main native species. Vernal Witch Hazel (H. vernalis) is also blooming at this time. The flower color of this species are variable, ranging from yellow to red. It is originally native to Arkansas and Missouri and usually found in moist soils.  This photo shows a branch with 'everything on it.'  As with the flower color, its tendency to hold leaves is also variable among individuals.

The other ‘native’ is the Common Witch Hazel (H. virginiana). This species is widely distributed in the Eastern US and is normally found in upland woodlands. The bright yellow flowers of this plant open up in the fall, while the leaves are still attached, so it is easy to miss them.

One place to see these plants in the Boston area is at Mount Auburn Cemetery.  You can also see more Mount Auburn photos at the Friends of Mount Auburn Flicker page.

While the origins of plant names can be rather fuzzy, one that stuck in my mind for witch hazel is that it often gets ‘warts’ on its leaves due to a gall formed by the spiny Witch-Hazel gall aphid. The red-tinged galls have long spines that look something like a hairy wart. In most cases these galls do not do serious harm to the plant.

Monday, March 1, 2010

Bidens in the Garden --- Beggarticks, weeds or not?

The name Beggarticks may not give you a warm, happy feel for a plant to add to your garden. Many of the plants in this genus do not have strong aesthetic qualities that appeal to the general public, BUT a few of these do and are worth considering.  This is another chapter in my experience of working with native annuals and biennials.

Most Bidens species share the trait of having seeds that stick to anything passing their way. In Latin, bidens refers to having two teeth, in this case the two teeth on the seed. The flowers of many Bidens species have diminutive yellow to white ray flowers, rendering the bloom insignificant for the human observer, but still just as valuable to insects (its the disk flowers that matter). Also these plants produce a lot of seed that can be long lived in the soil. With these caveats in mind let me mention several species that have greater visual appeal and can work well in a garden setting.

The first is Swamp Marigold, Bidens aristosa var. mutica. This plant is the exceptional in that it has the largest ray flowers of the genus. Also, while the seed possesses the two teeth typical of the Bidens, these are not able to catch hold like the others. B. aristosa’s range extends from the Maine to Georgia and as far west as Oklahoma.

As the common name implies, Swamp Marigold’s native habitat is wetlands, growing in full sun, or part sun on a woodland edge. Its growth habit is upright with many branches, forming a rounded shrub-like plant 3-5’ in height. It produces a large number of sweet scented yellow flowers, measuring to 2” in diameter. Blooming begins August with a burst of color and continues to October at a slower rate. Flowers are very attractive to bees. I have found that deadheading was effective at improving the second flush of blooms. Also the blooming period was independent of the location of the plant. Plants in pots, different soils, sun and moisture conditions all started to bloom within 2 weeks of each other. If you want a smaller plant, it can be cut back in late June without compromising the floral display.

Unlike many other tap rooted plants, this plant tolerated transplanting well. While somewhat stunted in size, plants transplanted from small pots into the ground as late as July, still put on a good show. I also noted that wherever the stem touched the soil, new roots would be produced. So while the best habitat for the plant is in wet soils, I found it to be adaptable to drier soils, even to the point of surviving as a container plants that were repeatedly dried to the point of wilting!

Seed for Bidens aristosa var. mutica is available from several sources including Prairie Moon Nursery. In my test moist stratified seed (90 days/40F) showed a very high rate of germination. In fact, germination had started while still under refrigeration in the dark. One potential difficulty in a native annuals garden is that the seedlings look the same as those for 'weedy' B. frondosa, Devil’s beggarticks. Differences will become apparent as the mature leaves appear, the leaflets of B. aristosa are much more deeply toothed.  In my garden I have Sulfur Cosmos (Cosmos sulfureus) growing from seed in the same bed. The plants look very similar, but the first set of true leaves of the Cosmos are rounded, not pointed. Also the Cosmos comes up several weeks after the Bidens seedlings first appear.

There are three other annual Bidens native to the Northeast US worth mentioning here. All of these grow 3-4 feet tall and prefer moist to wet soils.
  • Smooth Bidens, B. laevis, has flowers that are slightly smaller and nod downward when in full bloom. Seeds are available from Native Ventures in Louisiana.
  • Nodding Beggarticks, B. cernua, also has smaller flowers, but the bloom starts as early as June, extending to Septmeber.  
  • Northern Tickseed Sunflower, B coronata.  For the taxonomists out there there corrected name for this plant is B. trichosperma, but it will take some time for this to be updated.  Seeds for these last two plants are available from Prairie Moon Nursery.
All three of these species are indigenous to the eastern half of Massachusetts.

I will be trying out the Northern Tickseed this year and comparing it to the Swamp Marigold. One thing I will watch for is how popular the flowers are with pollinators. Northern tickseed is a Massachusetts native, while the swamp marigold, while found in the wild, is not listed as indigenous to Massachusetts.

Bidens ferulifolia – Apache Beggarticks

The last member of the genus I will mention here is Apache Beggarticks. These are low growing perennials originally found growing in open fields in southern Arizona and into Mexico. As the species, this plant has small yellow flowers; however, a number of larger flowered cultivars have been developed that perform well as annuals in gardens here in the Northeast. The species name ferulifolia is a reference to the fennel-like foliage.

Several cultivars of this plant are available as seeds and as small plants from nurseries. An example is B. ferulifolia ‘Peter’s Golden Carpet’ available from Proven Winners. This cultivar grows 10-15” in height and spread, producing copious amounts of honey-yellow, 5-7-petaled flowers, 1-1.5” in diameter, from mid-summer to frost (earlier if starting from nursery stock). This Bidens likes full sun and average soil moisture (mesic), thought it will tolerate droughty conditions. These plants perform well on the front edges of a border and in hanging baskets. Plants that I have observed returning from seed in Cambridge, MA have retained the character of the cultivar over least 3 years.