Water Young Trees in Summer

If you planted a tree within the last two or three years (congratulations!!!), it is still in the vulnerable stage of early root growth. Young trees need to be watered once a week, or twice a week if the weather is especially hot and dry.  The amount of water needed depends on a variety of factors including tree size and how well the soil drains.  Here are the watering guidelines in my area, from the Arlington County, VA website: 

Trees planted within the past two years that are less than 6 feet tall need a minimum of 5 gallons for each watering.  These trees should be watered at least twice a week starting in April and continuing through November.  Rainfall should not be considered adequate unless it is 2" or greater. 

The best time of day to water is early in the morning so that the amount of evaporation is minimized.  Late in the evening is the second best time.  The amount of water that comes through a hose varies for a variety of reasons such as hose size, length, size of the building's plumbing, water pressure, etc.  However, you can still estimate that about two gallons of water flow through a typical garden hose per minute.  This is roughly comparable to the amount of water that flows through the typical shower. Therefore, you should water newly planted trees for at least (3) three minutes with an unrestricted hose.  Hoses with sprinklers may need to be run longer since sprinklers may restrict the amount of water that flows each minute.

Casey Trees of Washington DC recommends "25 to Stay Alive", meaning 25 gallons per week, but the amount of water needed each week depends on the local precipitation and temperature. During the summer months, Casey Trees posts weekly tree watering recommendations on the main page of their website. Check it if you‘re unsure how much water your trees need. You can also sign up to follow them on Twitter, and that way you can receive reminders to water your trees.  If you don't live in the National Capital region, look for tree advocacy organizations in your area for information on the specific needs of the trees in your ecological region.

If you use a slow-release watering bag such as a  Treegator or an Ooze Tube, re-fill it each week from May to November.  These bags should be removed after two years. Arlington County, VA has a water truck and staff dedicated to watering street and park trees during the summer.  However, if you are within hose-watering distance of public trees that appear to be in distress, consider doing the trees and the community a favor and give the trees a drink. The watering bags can be tricky, so go ahead and visit the Treegator website for instructions. My neighbor Cheryl was motivated to fill the Treegator on the county street tree in front of her home, but it was so confusing that she wrote an article about it for our neighborhood newsletter to show others how to do it after she figured it out. Here's a link to her article, "Solving the Water Bag Mystery," in our civic association newsletter (hint, it's on page 8).

For more information on tree care, visit the TreeStewards website. Also, check out some of the great links over there to the right, such as the Tree Owner's Manual, a free downloadable, printable book from the USDA Forest Service, with everything you need to know about planting and caring for trees. =>

Cory's Baked Native Garden

Today was the hottest June day in Washington, DC in recorded history, at 104 degrees F.  It's been over 100 degrees F. for a couple of days now here in Northern Virginia, and I'm watching as my native garden bakes. Leaves are drooping, flowers are turning brown, and not even early morning watering perks them up. I'm watching four years of planning, purchasing, planting and nurturing native plants as they wilt, and I'm wondering if they will be hardy enough to withstand this assault. I'm hoping that, as natives accustomed to this climate, they have programmed in their genetic code a mechanism to protect themselves from this dry heat.  And if the leaves and flowers don't hang on, will there be time this season for the plants to grow new leaves and flowers?

I tout the benefits of growing native plants to my neighbors, and one of the selling points I use is that the plants don't need as much care, don't need as much water, don't need fertilizer, because they have adapted to our soil and climate over thousands of years. I guess what we're going to see is how well they handle an extended period of dry heat.

We just got hit with a frightening and severe thunderstorm tonight, a rare weather event called a Derecho, which is sort of a long, horizontal tornado, fueled by dry heat on the front side and cooler rain on the back side. The derecho caused a huge, multi-state swath of downed trees, deaths and power outages. Hundreds of thousands of households, businesses and government agencies lost power for days. We were very lucky in our home to have no damage, but there were trees snapped off like toothpicks, with at least 5 trees blocking streets within 5 blocks of our house.  We hosted one family seeking refuge from their unbearably hot house, and others stopped by to charge phones and cook food to use it up before it went bad.  Actually, I observed a great deal of  camaraderie and cooperation among neighbors over the last few days.  The storm brought the temperature down about 20 degrees in 20 minutes, but the temperatures are going to stay in the mid- to high 90s for the next nine days. Poor plants. Poor bugs. Poor birds. Poor mammals.  We shall see how this all turns out.

Tree Canopy Fund - Trees for Private Property

Arlington County, Virginia has a unique and innovative program to enhance the County’s dwindling tree canopy coverage. While the County has funding and jurisdiction to plant and maintain trees on public property such as streets and parks, the greatest amount of available space to plant trees is on private property. In 2007, a program was developed that provides funds to help homeowners and other private property owners to plant trees on their land. 

The funding is provided by property developers who are unable to place the number of trees required by their site plan on their property when they develop sites. The developers must pay $2400 for every required tree they are unable to plant on their site. This money is used by a local environmental non-profit organization called Arlingtonians for a Clean Environment, to administer the Tree Canopy Fund. Trees are planted for the homeowner by a carefully selected nursery that is able to provide high quality trees that meet the size, species and planting guidelines of the program.

Under this program, community groups such as Civic Associations and Condominium Associations can apply for the funds to have trees planted on their property. There is an emphasis on large, native canopy trees that will provide a number of ecosystem and economic benefits such as street and sidewalk protection, home cooling, stormwater slowing and filtering, carbon sequestration and oxygen production, and wildlife habitat. Applicant groups are encouraged to work with trained TreeSteward volunteers from their neighborhood to help homeowners to select appropriate trees for their site, and to place the tree correctly on the site to meet as many benefits as possible and to avoid hazards such as proximity to power lines.

Arlington County is a suburban community that is quickly becoming urban. Its location adjacent to Washington, DC makes it a desirable location to live and to develop for government-related enterprises.  But this development has caused Arlington to lose a significant amount of tree canopy coverage. Under the Tree Canopy Fund, so far 688 trees have been planted for homeowners by contractors, and funded by the Arlington County Tree Canopy Fund.  To learn more about the fund, visit the Arlington County website http://www.arlingtonva.us/departments/Communications/PressReleases/page58308.aspx to read a press release announcing and describing the program. Details about the program, the process and the tree selection list can be found here

http://www.arlingtonenvironment.org/trees

I encourage you to learn about this program, which demonstrates Arlington County’s commitment to maintaining and increasing a healthy urban forest for all of the vital benefits that it provides. Increasing urban tree canopy coverage using appropriate species in the appropriate location is valuable nationally and globally, not just locally. If you can use our program guidelines and procedures to develop a similar program in your community, I would be ecstatic to know you learned about it from me.

To learn more about trees and the importance of planting locally native species, please visit the links on the right ==>

Luna Moths Need Black Walnut, Hickory Trees and Dark Skies

Luna Moth (from Wikipedia)

Two decades ago when I moved to our house in Arlington, Virginia, a Luna Moth took up residence for a couple of days among the moon flowers and morning glories climbing up the bean trellis. Since I was new to Virginia as well as the neighborhood, I assumed Luna Moths were a common occurrence that I would be able to enjoy in my new home. That turned out not to be true, and I’ve only seen two, both more than a decade ago.

 

The Luna Moth, Actias luna, is a lime-green swallowtail with a wingspan of four and a half inches, making it one of the largest North American moths.  Its preferred larval host trees in our area are the walnuts and hickories, but it will also use sweet gum and persimmon trees.  Up north, they go for birch, alder and sumac.  The trees are not damaged by the caterpillars.  After eating their fill of leaves and transforming through five instars (life cycle phases or molts), the caterpillars drop to the ground at the base of the tree, wrap themselves in silk and leaf litter, and pupate.

 

Luna Moths face many challenges to survival in the urban sprawl.  They require dark skies to reproduce.  They fly up to the tops of the host trees well after midnight to mate and lay eggs.  There is evidence that the bright lights from streetlights and buildings interfere with the moth’s ability to reproduce. They are also becoming endangered by the measures to control Gypsy Moths.  

While I haven’t read anything about the effect of leaf collection on Lepidoptera, it seems logical to me that our obsession with raking, mowing and blowing our yards clean has had the effect of sweeping away the pupated moths and butterflies as they undergo the miracle of metamorphosis at our feet.   [for more information on supporting wildlife by leaving in place the  leaves, seedheads and leaf stalks that insects, birds and small mammals depend on, see this post by Pat Sutton "A Love of Untidy Gardens and Why!" on the website Native Plants and Wildlife Gardens]

Finally, as our neighborhood’s original native tree cover is aging and disappearing, we are not replacing them with the species that the local fauna require for food, shelter and reproduction. Maybe we can help keep these beauties around by planting native hosts, leaving some leaf litter each fall, especially at the base of walnuts, hickories and sweet gums, and turning off unnecessary lights at night.

 

For more information on native landscaping for wildlife, have a look at the links on the right =>

Update May 27, 2012: We went for a walk this morning at Huntley Meadows Park in Alexandria, Virginia. On the path of the forested area near the edge of the wetlands, I saw a Luna Moth. It was the first one I have seen in almost 20 years.

Flying Squirrels Need Tall Trees

Photo by Steve Young

Recently I was browsing the website of the Arlington Virginia Long Branch Nature Center when I spotted a link to this great  video about the Southern Flying Squirrel. Unable to resist watching the video, I learned that there are probably more Southern Flying Squirrels here in Arlington than regular grey squirrels. We just don't see them because they’re nocturnal. They live in pretty much the same backyard habitats as the grey squirrel. They need a hiding place, water and food. In the video, a staff member of the Long Branch Nature Center is demonstrating the behavior of the flying squirrel by showing how it will fly to a tree that has peanut butter smeared on it. In another Long Branch Nature Center video, you can see a flying squirrel up close. This is the resident flying squirrel that lives inside the Long Branch Nature Center. This squirrel was rescued and brought to the nature center in 2007.  He refuses to live in the wild. As a result, he is a wonderful learning resource for Arlington residents.

The Southern Flying Squirrel is the mascot of the Long Branch Nature Center, located in Arlington, Virginia. It’s on their brochure, and they lead night walks to spot the animals.   To learn more, I interviewed former Director of the Center (currently Director of Natural Resources for Arlington County), Alonso Abugattas, our resident expert on the Southern Flying Squirrel. 

The flying squirrels are smaller than grey squirrels. They have larger eyes to see better at night. And they’re more predatory. In addition to nuts, fruits and berries, they’ll eat animals, insects, eggs and carrion. Their favorite nuts are hickory nuts but they also like filberts and oak acorns. They don’t like walnuts so much because they’re hard to carry. They love suet and seeds from bird feeders.

Flying squirrels don’t actually fly. They glide from one tree to another.  They spread out their skin flaps, called a patagium, and catch the air like a parachute. They control the glide by banking.  They don’t use their tails to steer. Sometimes they wipe out on the ground if they miscalculate. For every two feet up, they can glide one foot out. The longest glide observed was 100 yards, off a tree and down a hillside.

Photo from "The Snag" Newsletter of Arlington VA Parks and Rec

Flying squirrels can build leaf nests (dreys) but they don’t like to live in them.  They prefer cavities in live trees, dead trees or snags. Keep your dead trees standing if possible and safe, or cut them down to a safer height, retaining the snag. They will also nest in bluebird boxes. They prefer to be at least 10 feet up.

During non-breeding season they hide together in cavities to keep warm. During breeding season they are incredibly secretive. They spread out in the woods. They prefer a habitat with big trees, larger, older trees that are spread out a bit, 20 feet apart or more.

In suburban areas, if there aren’t enough trees, they will take up residence in other areas such as bird boxes and attics.  This can be a problem because they run around at night and they chew.  If this happens, they’re easy to trap in “Have a Heart” traps with peanut butter as bait. 

To see flying squirrels in your yard, put peanut butter on a tree branch after the grey squirrels have gone to bed. I haven’t tried it yet but I will soon!

Plant and preserve native canopy trees so flying squirrels and other wildlife have a place to live. 

For more information on the Southern Flying Squirrel, check out the website of the Chesapeake Bay Program. There's also a fact sheet by the Audubon Society of Northern Virginia, that gives advice on how to provide food and shelter for the Souther Flying Squirrel by planting native berry shrubs and hickory trees.  Also plant butterfly host plants because they love to feast on caterpillars.

-Cory