Sunday, August 28, 2011

North Point Park, Cambridge, MA

I have heard, on and off, about the construction of North Point Park as a 'set aside' from Boston's Big Dig.  It's in an area I always shied away from because of the the traffic.  But on a quiet day last Sunday and a reminder from some landscaping associates I finally made the short trip into East Cambridge.

The 8.5 acre park was opened in Dec. 2007 and is on the north bank of the Charles River just east of Boston's Science Museum.  For backgound on the history and construction I will refer you to a Wiki article and item from the Boston Globe.  The design was done by Carr Lynch & Sandell of Cambridge and Oehme van Sweden of Washington, DC.  Van Sweden is noted for their use for grasses, and it shows well in this park. 

View looking northeast into Cambridge.
 The park is designed for multiple uses and, on my visit, it seems to do them well.  The landscape is varied.  There are large open areas for lounging or more active pursuits.  There are playground areas that are clean and modern.  There are areas with dense plantings that offer some privacy and there are a couple of islands, linked by bridges.  All of these work together to form an interesting and diverse experience.  Another aspect that I found to be very nicely done is to have separate path systems for various modes of transport: Walking paths, Bike paths and Channels for kayaking. 

Playground with fountain spary.

A more secluded gathering area. 
I'm curious how this will be used.

A section of bike path around a stand of Prairie Coneflower.

View to the east.  Plantings had to be selected to deter use by geese.

One of the Kayaking channels.

Looking at the plant palette, I was expecting to see all native plants, but what is here is a pragmatic mix of natives and non-natives with the focus on design and survivability, rather than strict use of native species. Personally, would have like to have seen more natives, but visually, this design 'works'.

Mix of grasses including native Panicum and non-native Pennisetum.

View south toward Boston through a hedge
of non-native Corneilian Cherries (Cornus mas).

Liriope and a dwarf Summersweet (Clethra alnifolia)
form an effective groundcover.

My favorite combination: Joe-Pye Weed and Hibiscus hybrid ('Lord Baltimore'?)
 On this day the most striking plant compostition was the Joe-Pye Weed (Eupatorium dubium) and the hybrid Hibiscus.  One of the reasons I like this is that they are both wetlands plants native to the eastern U.S. (or at least derived from eastern natives).

My biggest concern for this park is how it will be maintained.  Will the beds be weeded out of invasives and plants blown in from other parts of the park, or will a form of succession be allowed.  I noticed a few patches of purple loosestrife and bittersweet growing among the plantings.  I also found a patch of Horsenettle (Solanum carolinense), a native of the southeastern U.S. that has spread across the continent.  This is a really well defended plant with thorns on its stems and its leaves.  Currently the park is not getting a lot of visitors.  I hope people come and take notice of it and insist that it get the maintenance attention that it needs in the coming years. 

Wednesday, August 17, 2011

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.