I:n this issue:
Two replacements for ash trees in emerald
ash borer areas
Update 2014 and a complete 28-tree list
In search of rare seeds
Mulch and bugs, AOK to let it be!
Thumbs up and down to fall rain and tending
Katsura and dawn redwood:
Good replacements for ash trees
Japanese katsura (Cercidiphyllum japonicum)
should be on your list of replacements for ash trees, as another
excellent tree. It's upright, has a nice shape and butter-yellow
leaves that all drop at one time in fall.
As for dawn redwood (Metasequoia
glyptostroboides) that's on your list, it's beautiful but it
requires a lot of space. One should allow at least a fifteen foot
square area. This is a tree you would not want to limb up as you
lose the beauty of the structure. This actually is not a shade tree
but a beautiful specimen that gets very broad at the bottom. It has
soft, sweet-smelling needles and apricot fall color. Since it loses
its needles in fall it looks dead in the winter which is not a good
look for some people. I did not provide enough room and recently
had to take mine out, which broke my heart. - J.T. -
The 28 trees on the list we've been sending out (scroll down to
read about it, and download a copy) are not the "last word" but a
great start. That list was compiled from the choices made by
city foresters with long experience in planting and maintaining our
urban forest. Beauty is valuable in that forest but secondary to
adaptability, dependability and availability.
The katsura is an outstanding tree. If we added it to the list,
it would be in the group that requires unrestricted root space, in
a large lawn or park. It would not thrive with its roots trapped
between street and sidewalk.
That places it with dawn redwood, which is big but shouldn't be
discounted as a shade tree, or a boulevard tree. People walking
near us the day we caught sight of dawn redwoods as street trees in
lower Manhattan gave us a wide berth when we both froze in place,
open mouthed and staring. Yes, the huge, fluted trunks rising from
openings in the pavement had been limbed up for clearance as they
grew but it did not detract from their beauty.
Many trees are groomed for their future use by the grower, so
that there are a number of trees most people wouldn't even know in
their natural form. Grooming often includes removing lower limbs as
the tree grows, even on a tree that would otherwise be branched
right to the ground. Pin oak, linden, hawthorn and magnolia all
have ground-sweeping skirts, in nature. Yet the first two are
commonly used as street trees, so we produce them without branches
below nine feet to permit pedestrian and vehicular traffic. The
last two are limbed up because we like to grow gardens and lawn
Chances are that when there were dawn redwood forests,
individual trees lost their lower limbs just as white pines do in
dense stands. We can't know this, since dawn redwood disappeared
from the wild centuries ago. The species survived as one cultivated
grove in China, eighteen trees widely spaced. All those we plant
today come from that one remnant of ancient times.
Or download our more detailed list:
In the Wake of Emerald Ash Borer:
Ash tree replacements
As the non-native insect, emerald ash borer (EAB), continues
killing billions of ash trees (Fraxinus species)
throughout eastern North America, there is as yet (2014)
little we can do to stop it. Here is a list of trees suitable for
replacing an ash at streetside or in your yard. It was compiled
from the choices offered by city foresters in our area, at the
epicenter of the emerald ash borer plague.
On our list we have included detailed descriptions of the trees.
For more about emerald ash borer, search those words here on our
site and visit the U.S. Forestry Service EAB information
page where you can learn about EAB status in your area, and the
latest on its control.
download the ash tree replacement list in pdf
In search of rare seeds
Do you know a source where I can find seeds that not
everyone seems to stock? I am especially looking for seeds of
a plant called Jamaican sweet pea. - M.B. -
How about Old House Gardens, a mail order firm specializing in
heirloom bulbs and plants? You can find them at www.OldHouseGardens.com.
We're not familiar with the common name Jamaican sweet pea. Do
you have the plant's scientific name, or more clues to go by?
Numerous plants can share a common name. So without a scientific
name, you might find nothing or be surprised to meet an unexpected
plant when you sprout the seed you buy.
Are there more insects where there is
When people scrape aside mulch, point and say, "Look at all
those bugs!" We say, "Just don't look. The vast majority aren't
hurting but helping you and the garden."
There may be more total types of insects in a mulched garden but
probably not more insects overall. Mulched soil is cooler and more
moist than bare soil, better for root growing and also more
attractive to certain insects, decomposers that break organic
matter into soil-enriching minerals and humus. Other insects come
to prey on the decomposers and may also stay to hunt plant-eating
insects in the area.
Mulch does not provide homes for ants or termites unless it
consists of abnormally large pieces of wood -- chunks or logs
rather than chips.
Green thumbs up
to the rain that finally came. Now the trees, shrubs, bulbs and
perennials we've planted in September and October can use the
season as they should, to get the jump on next year.
Green thumbs down
to planting and walking away. No matter how big and self
sufficient the tree seems, mulch it well then keep the new root
ball and surrounding soil moist until the ground freezes.
Originally published 10/23/04