Thursday, July 26, 2012

Lily of the Valley Tree--Sourwood

Leaves are similar to peach trees.
Sourwood trees are gems that only those who live in regions of clean air get to enjoy--urban dwellers need not attempt to plant a sourwood, as they don't respond well to pollution. They do not transplant easily, either. They don't like compacted soil, and they prefer moist, acidic soil. A rough winter will kill off smaller twigs. It doesn't grow very quickly, either. So why bother with this troublesome tree?

Oxydendrum arboreum, all alone in its genus, is a terrific specimen tree for smaller homes and properties that are large enough to have woodland edges. It has strong resistance to insects and disease. It blooms later in the year than most specimen trees--here in Transylvania county, sourwood trees at the lower elevations are blooming right now--and it has outstanding fall color, showing off brilliant red leaves. After the leaves drop, you will be pleased to see red twigs carrying on the theme. (Terrific photos of the twigs at the Duke Univ. link below.) While in the wild sourwoods can reach up to 75 feet tall, those in cultivation typically top out at about 30 feet and about half that in width--a good size for smaller homes. But unlike many other specimen trees, this one is strong--and a favorite of honey bees!

Bell-shaped flowers are bee magnets.
Sourwood gets its "Lily of the Valley tree" common name from its flowers, which hang bell-like from six- to eight-inch spikelets at the termination of the branches. Trees planted in full sun will bloom better and have the strongest fall color, but these trees are quite fond of partially-shaded locations if you have a spot available. As a habitat plant, sourwood attracts bees, butterflies and birds after seed has set. The twigs are likely to be browsed by deer in winter.

I recommend mulching newly planted specimens to help it establish itself in your yard, as the mulch will help to keep the soil more moist and encourage some insect activity to keep the soil structure more open. Sourwood is hardy in zones 6 through 9, though some sources include zone 5. I had to order ours through our local nursery--it was the first tree I'd ever planted that arrived in a wooden box instead of a plastic pot. I assume this was to help remediate the transplanting problem--the rootball had some of the healthiest development at the outer edges I had ever seen in nursery stock. I was interested in a single-trunk tree--but you may also be able to locate a multi-stemmed sapling that could be kept more shrub-like. If you choose to plant a sourwood, expect it to take the full three years to get established and start putting on its sumptuous, leafy skirt!

Color coming on last fall.
Speaking of leaves, those on Oxydendrum are between three and eight inches long, slightly serrated and alternate. The bark of mature trees is very thick and blocky. Unlike certain other over-planted specimen trees *cough* Bradford Pear! *cough,* sourwood grows slowly enough to have hard, dense, finely-grained wood. This one is unlikely to just toss its branches around the yard when you blow your nose. And unlike every other tree I can think of, sourwoods are even distinctive in their trunks--which are not round, but more oval/elliptical. See? You have to have one. You can purchase a sourwood through the Arbor Day Foundation, or you can pester your favorite local nursery to hand select one for you. 

Sources: Wikipedia, Duke University,, NC State, University of Connecticut, USDA Forest Service, Fine Gardening

Thursday, July 19, 2012

Throw A Log On It

Still life with viburnum, sensitive fern and log.
When looking at our yards as a place to build habitat, we naturally look to plants, first. After all, the berries on plants feed birds, the pollen and nectar in flowers feed pollinators--plants are essential to the wildlife garden. But how do you set up conditions for long term success for your plants? How can you build soil that isn't in constant need of amendments?

One answer is to provide food for soil flora and microorganisms. One way of providing this food is to mulch beds so that soil moisture is moderated, and shelter is given to the surface of the soil--which invites those organisms to play. But another thing you can do is give these little, sometimes unappetizing critters a more "permanent" shelter structure--a hunk of dead tree.

Tree hunks decay at different rates depending on weather and the activity of plants, animals, insects and bacteria, to name a few. In addition, the species of tree itself will have an impact--hardwoods will take longer to decay, in general, than softwoods. And of course, if the dead hunk of tree is black locust--well, that might take a really long time!

The primary job of this hunk of wood is to be an insect house.
On the forest floor, decomposing logs may be a hazard to hikers, but they are vital to the overall diversity of life found in the forest. One-fifth of all woodland creatures live in them! That's a bunch of critters! Most of these are small or very small, and therefore not nearly as exciting as oh, say--a mountain lion. But the role these dead hunks of wood play is essential to habitat and it is easy to replicate this habitat in the home garden.

For instance, in the photo at right, this old piece of spruce tree marks a change in elevation between one part of a shrub/tree border and another. Behind the log the soil is about six inches higher than the front side of the log. When walking in the landscape, you would have to look hard to see this log--it is hidden by shrubs, trees and irises. Small holes from tiny beetles are all over it.

Dead log critters tilling the soil and adding "deposits."
This next photo shows soil directly beneath a log that has been in position for almost two years. If you look closely, you'll see a slug on the left and centipede near the top right. Notice how rich and crumbly it looks. Probably just a massive pile of insect poo, which my azaleas greatly appreciate! Logs suck in moisture when it is available and then release it slowly into the ground during drier spells. Think of it as a soaker hose on a timer. Which does not mean that you're going to want to litter your yard with a truck load of logs, but maybe you can see how a few might be helpful, especially if they go into place during the non-planting seasons, so they have reached a greater level of absorbency before drought season. The more decomposed/broken down they are, the spongier they get--making them even more effective as soil moisture moderators. They also excel at filling the bottom of raised beds--breaking down slowly, but in the meantime holding moisture for the gardens planted on top of them.

These spruce logs have been abused by pileated woodpeckers.
Old dead hunks of wood can become homes to small mammals like shrews and (even better) to toads and amphibians. I like to think of toads as slug-eating machines. Therefore, I am wildly hopeful that once I put in my toad-friendly water feature, my yard will benefit from many happy toads. (*update, 8/2013--even without the water feature, the logs are helping. Finally have toads this year!)

But I digress.

You can use logs to create terracing much like you would use garden boulders. The difference is that logs will need a bit of a trench so they can be partially buried, if the hunks are relatively small. After "heeling in" the log chunks, plant on the uphill side of the log. The logs will help trap water for your new plants while they get established.

A mixed log and rock terrace edge in a meadow planting.
Adding logs to the landscape can be an actual design feature. Or it might be a necessity, if you end up with huge chunks of dead tree. That was the case with us when neighbors on both sides took down spruce trees. In addition to all the spruce, we also took down a silver maple tree (not the strongest of trees) and replaced it with a sourwood. The maple was only a foot in diameter at the base when we took it down, but you'd be amazed (well, maybe you wouldn't!) how much log can be acquired from one tree! The maple was dealt with partly in the fire pit (ashes were composted) and partly through "installation" in the yard.

Having some logs within your landscape will definitely improve your songbird activity. Many of the creatures that like to consume logs are things that songbirds like to consume.  I absolutely adore watching the wrens and song sparrow "work" a log for insects. As the bark loosens, they will sometimes disappear right under it as they poke around for juicy bits. If you love birds, you will definitely want to add some dead tree hunks to your habitat! Be sure to check the Smithsonian link in the resources for some excellent photos of some of the organisms that munch down on old dead hunks of wood.

Hard to tell this guy is hanging out in an old log, isn't it?
Logs are an almost essential addition to the landscape in a woodland garden, but meadows or border gardens can take advantage of them, as well. For a meadow, try getting hold of a long, twisty branch to lay near a birdbath or bird feeder on a post or hook. This will give your birds a foraging spot to catch insects that are after the seed hulls littering the area under the bird feeder, or a landing spot from which to enter The Bath. In a border garden, try using some small logs as edging. Either way, you will be supporting diversity in your home habitat in some surprising ways. So get out there and throw a log on your yard!

Tuesday, July 10, 2012

Carolina Phlox Courting Diablo

Cultivar of Phlox carolina, a mildew-resistant summer bloomer. This one is 3 feet tall, with ninebark "diablo" behind.

Tuesday, July 3, 2012

Invincible Vines for an Invincible Lady

Joyce with a few of her 250 milkweed plants!
Lately we've been involved with a project full of potential for the promotion of native gardens. But before I tell you more about the project, I have to tell you about the reason we're involved in the project. That reason would be an Aggressive Gardener by the name of Joyce Pearsall.

Joyce, like many good Master Gardeners in Transylvania County, is a transplant to the area. She was dragged to the county kicking and screaming--well, no, not really, but her husband Frank did have to work on her for awhile. Anyway, they decided to retire to Brevard, NC. Great for me. Absolutely fabulous if you were born a monarch butterfly and find yourself in this county!

A monarch caterpillar pupating in Joyce's monarch nursery. 
Monarch Momma, as I sometimes refer to her, takes monarch caterpillars out of the garden setting and into her nursery where she feeds them an extensive diet of milkweed leaves until they successfully pupate. Once they hatch out, she tags and releases them so that when a tagged monarch is recovered, the data of the find can be added to an existing database to help scientists better understand migration patterns of monarch butterflies.

Joyce has installed over half a dozen Monarch Waystations in Transylvania County. A Monarch Waystation (you can certify yours here) is designed to provide plants that monarchs need as a food source for both the adults and the caterpillars. Without nectar, they can't make it through the end of migration. Without host plants, we don't get any new monarchs! The host plants are especially important, since monarchs, like other butterflies, can get nectar from many different plants. The only plant that will work as a host plant, however, is one of the milkweeds. You can read more about that in the links at the bottom.

Joyce's latest project is the updating of the gardens surrounding the Pisgah National Forest Ranger Station located in Transylvania County. The original plantings were well thought out, but many were overgrown, and some species had choked out others. Joyce has been working on this for quite awhile by herself and with other volunteers to get the growth in check, remove invasives that had found their way in--and of course to establish a new Waystation.

Part of Joyce's philosophy of design with this very public space was to create a space so attractive and accessible that regular homeowners would think to themselves, "Well, I could do that!" She also wants to make sure that information is close at hand so that casual gardeners can find out about why it is so important to plant milkweed and nectar plants to support monarchs and other wildlife. Every native is being labeled. Posters will be framed and hung. And a few new additions to the plant list are making it into the ground.

New trellis with Lonicera sempervirens.
Two of the new additions are vines. There are a number of native vines that birds--and particularly hummingbirds--really enjoy. Trumpet vine (Campsis radicans) and Carolina Jessamine (Gelsemium sempervirens) are both extremely vigorous vines with a huge hummingbird fan base. Really, really vigorous. As in "need constant supervision." At an understaffed, federally under-funded ranger station, these vines probably would not get constant supervision. Therefore, these two vines, while delicious, are not good choices for this particular setting.

We needed to get some evergreen presence into the gardens, without plugging in something with a very large footprint. So a native evergreen vine would be a lovely thing, as long as it would be relatively well-behaved. And we have two winners!

2nd trellis with crossvine.
Coral (or trumpet) honeysuckle (Lonicera sempervirens) and Crossvine (Bignonia capreolata) are two really wonderful vines for small garden spaces. They take pruning well and are enjoyed by multiple species. They just need a good place to park their roots before they take off. Of the two, crossvine is the showier plant, absolutely loaded with blooms at the appointed time, and could hardly be more trouble-free. Wet soil, dry soil, sun or shade--you really ought to get yourself one! It serves as a host plant to the rustic sphinx moth, and blooms for about four weeks just as ruby-throated hummingbirds are migrating north. Some horticulturalists have said that crossvine produces more flowers per foot than any other plant. How's that for an endorsement? We simply had to get one for Joyce's latest project.

Coral honeysuckle is a more subtle bloomer than crossvine, but keeps at it for a longer period of time. And like crossvine, coral honeysuckle benefits hummingbirds, butterflies, bees and many other species of bird. But despite its well-behaved demeanor and its extensive value to wildlife, this vine is creeping up the endangered lists in much of its native range. Like crossvine, it is not picky about soil, is very pest and disease resistant, and can handle sun or shade. When coral honeysuckle is planted in full sun, you will do it a favor to shade its roots and water well as it gets established. It is a host plant for the spring azure butterfly--the fruits are enjoyed by bluebirds, cedar waxwings and gray catbirds, among others.

Joyce's vision to get more people involved in gardening for wildlife--and particularly monarchs--is one many people share. Her drive, however, is exceptional. I hope you have a Joyce in your life to keep you inspired about gardening for wildlife!

Sources/Links: Planning a Monarch Waystation,  Not the Day I Planned, Monarch Butterfly, Asclepias spp., Pisgah National Forest, Lonicera sempervirens, Out My Backdoor: Crossvine, Mississippi State: Coral Honeysuckle, GWF: Coral Honeysuckle    

*Native Backyard's home address is certified as a Monarch Waystation.

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