Sunday, December 25, 2016

Jolly Holly

Possumhaw (Ilex decidua)
Hollies are one of the most used plants for winter decorations such as Christmas. The most familiar species are the evergreen ones that have bright red berries such as American holly (Ilex opaca). In Georgia, this species is widely distributed throughout the state and makes a fine landscape tree.

Hybrids of American holly are used in landscaping more often than the plain species; Ilex x attenuata cultivars are crosses between Ilex opaca and the southern dahoon holly, Ilex cassine. Hybrids such as ‘Savannah,’ 'East Palatka,’ and ‘Fosteri’ are robust female plants with heavy fruit set (and fewer spines on the leaves) that require little to no cross-pollination. Some of these hybrids were found in the wild as natural crosses.

American holly (Ilex opaca)

Yaupon holly (Ilex vomitoria)
Yaupon holly (Ilex vomitoria) is an evergreen holly that is also often used, even outside of its natural range in the Coastal Plain. It is popular for several reasons. It has small, spineless evergreen leaves. It grows well in landscaped areas throughout the state. Several dwarf forms are suitable as small shrubs such as around home foundations (where they are sheared into meatball shapes but I think they look great when left unpruned as well). Female plants, which are not usually the dwarf forms, have tiny red fruits that have a bit of a translucent look, quite different from of the opaque berries of American holly.

Georgia has two other evergreen hollies located in the Coastal Plain: dahoon holly (Ilex cassine) and myrtle holly (Ilex myrtifolia). Both have red fruits.

Red-fruited hollies are not always evergreen. Georgia has at least 6 species of deciduous hollies, all of which have red fruits. The leafless winter stems of these species can be spectacular and the horticultural world has noticed. Cultivars of both possumhaw (Ilex decidua) and winterberry (Ilex verticillata) are available in the trade. When choosing, be sure to determine if you’re buying a male or a female and that you have compatible males and females eventually (you can have more females than males).

Ilex verticillata
Ilex decidua

The remaining deciduous native hollies in Georgia include two in the Coastal Plain (Ilex amelanchier and Ilex ambigua) and two in the northern part of the state (Ilex montana and Ilex longipes).

Ilex glabra
Evergreen hollies don’t always have red fruits. There are several species that have dark blue fruits. The two species in Georgia are large (or sweet) gallberry (Ilex coriacea) and the smaller one known as inkberry (Ilex glabra). Both like to grow in moist areas. Inkberry can be found in the nursery trade and is available in forms that are dwarf and compact; look for ‘Shamrock,’ ‘Compacta,’ ‘Nigra,’ and ‘Densa’ and carefully check for male/female suitability if you want berries (the ones listed are noted as females while ‘Nordic’ and ‘Pretty Boy’ are male).

Native hollies are great additions to the home landscape. They are beautiful, adaptable and important to wildlife. The small but numerous flowers are important to native bees. Gallberry honey, which is produced by European honey bees, comes from nectar gathered from Ilex coriacea and Ilex glabra. All the berries are popular with birds that eat fruit. Consider adding a regionally appropriate holly to your landscape next year.

Sunday, December 18, 2016

Atlas of Georgia Brings Herbaria to the People

When I find plants that are new to me, I do try to identify them. I use a variety of tools, including books and online resources. Many times, after an initial investigation, I might be in the position of comparing 2-3 species in order to reach what I think is the final identification. Identifying asters in the fall is such a case. Pictures can be very helpful at this point, but pictures on the web don’t always have the appropriate details or, even worse, might be misidentified by the person that posted them.

Choose Browse or Search Collection here
A new tool came online this year and I’m pretty excited about it. The Atlas of Georgia Plants portal is a means of viewing vouchered herbarium specimens from the University of Georgia and Valdosta State University herbaria. Over 100,000 specimens, some dating back to the 1800s, have been digitized and are now available for online viewing with more to come.

You can browse the collection by Family, by Genus, and by County. From the navigation menu, choose “Browse Collection” to get started. Some collections are quite large and some are quite small. Some counties have very large numbers of specimens. The same is true for certain plant species. Having a large selection of specimens gives you more to examine which is good; some are in better shape than others. Detail varies by specimen; some of them include roots, most flowering perennials that I checked do include the flowers.
The General Info tab of a selection

Most people might find it more efficient to use the search capability. From the navigation menu, choose “Search Collection” to enter your search criteria such as Genus and Species (e.g., Quercus for genus and coccinea for species). 

This screen has a nice feature: as you type, the webpage is finding matches for you. For example, after having typed “coc” in the species field, you have seven choices already and can choose “coccinea” from the list. You can refine your list by adding county as well.

Image sheet with zoom capability

Once you have found a specimen that you want to examine, double-click on it to open it. This opens the “general info” tab. To see the specimen, click on “image sheet” in the secondary menu. Once you’re in the image sheet, you can zoom in on the specimen if you first choose the option “Switch to interactive view” at the bottom of the page.  Go back to the “Static view” when you are done. 

When you are ready to close the specimen, close it from the top menu by x’ing the specimen number (this is an 1895 specimen of scarlet oak collected by James Small, numbered as “GA084077”). You can keep multiple specimens open at once; just click “Search Collection” again to get another one without closing this one.

Note that some are marked “poisoned.” This means that they were treated against pests.

You can see distribution information at the bottom of the species page (before you select a specimen). In addition, you can find pictorial depictions of distributions at this linkThis link has Alphabetical letters for plant families (e.g., choose “F” to go to Fagaceae if you want to search for Quercus (oaks) or “C” for Caprifoliaceae for Lonicera (honeysuckle)). From there, choose the species you want to go to the distribution maps. I like the list of county names so that I can quickly check which counties have presence rather than trying to figure out the counties by staring at their shapes on a map.

I compared the distribution map to the USDA distribution for chalkbark maple (Acer leucoderme); there are a few differences at the county level but the general distribution is the same (herbarium records might be driving USDA maps, I am not sure).

In general, this is another tool in our kits for identification. If you're in Georgia or nearby states, you might give it a try and see what you think.

Sunday, December 11, 2016

In My Own Backyard

I feel like a fool. For years I have been curious about oaks in my area. In my neighborhood, in the places where I shop, on the field trips that I take … all of these have been places to discover oak trees. I have collected leaves, picked up acorns, and inspected twigs in efforts to identify them and published blogs that detailed my findings. This fall, in my own yard, I finally realized that I had a species that I had never identified – blackjack oak (Quercus marilandica).

Blackjack oak (Quercus marilandica) over the driveway
I had noticed saplings of this unknown oak shortly after we moved here, next to the driveway. The leaves were thick, sometimes glossy, hairy on the back, and shaped like a cartoon foot with 3 fat toes. In the fall they would turn beautiful shades of deep red. I thought that they might be post oaks (Q. stellata). At some point, I figured out that they were not post oaks and that was it. Apparently, I never thought about them again.

My blackjack oak sapling

This year’s brilliant fall colors reawakened my curiosity, and I got out my favorite oak identification resource again. Blackjack oak seemed to be a good match based on leaf shape. The range seemed a good fit such that it would be in this area.  

It seemed odd that I would only have smaller plants; I had never seen any large ones in the neighborhood.

A few days later I was walking around the yard and I noticed the leaves on a low branch coming off the trunk of a large tree out back. Was that the same leaf as the smaller plants out front? I gathered leaves from the low branch and went back to the books. 

I contacted a knowledgeable friend and sent pictures. He pointed out that Weakley's identification keys pointed to a closer examination of the length of the petiole and the hairs on the underside in order to differentiate it from Southern red oak (Quercus falcata). I gathered a few Southern red oak leaves and compared them; my leaves clearly pointed more toward Q. marilandica var. marilandica.

Further research shows that it could be a hybrid with Quercus falcata) which is also in my yard. Either way, I am thrilled to have this one figured out. I could not find any fresh acorns this year, but I'll be on the lookout for them in the years to come.

Sunday, December 4, 2016

Parking Lot Maples

It’s been a good year for maple trees in terms of fall color, and their widespread use as a parking lot tree has made that very noticeable this year. Some of you might be noticing these trees for the first time, and might be considering one for home use, so let’s talk about what these are.

Twenty to thirty years ago, we saw the widespread use of ornamental pears (Pyrus calleryana ‘Bradford’) in parking lots, professional landscapes and the yards of new homes. Eventually, people realized that those pears were prone to breaking, had smelly flowers, and were even becoming invasive plants. Landscapers searched for replacement trees, especially in parking lots where trees have to tolerate tough conditions.

I’ve written before about the many types of oaks used as parking lot trees, and those are still in use. I’ve seen some very good looking “pin oaks” in new parking lots, but I imagine that acorn drop can be a problem depending on location. A variety of other trees, including red maple cultivars, are being used as an alternative.

Acer rubrum 'October Glory'
Acer rubrum 'October Glory'

Two red maple cultivars seem to be getting the most use. The first one is Acer rubrum ‘October Glory’ which has a typical red maple leaf shape (3 lobes), a well-balanced oval shape, and a deep red fall color that leans a bit more towards crimson-red than orange-red. According to the patent record for this cultivar, it was selected not just for color but for long leaf retention in the fall. That trait was certainly evident this dry fall when leaves have persisted even past the third week of November, often all the way up to the top of the tree.

Based on an informal sampling of parking lots in my area, I would say that ‘October Glory’ is used most of the time (and for good reason if long lasting color is your goal). Occasionally, I find the second cultivar which is actually a hybrid of red maple and silver maple (Acer saccharinum) known as Acer x freemanii ‘Jeffersred’ but sold as Autumn Blaze®.  The Freeman hybrids were developed in 1933 at the U. S. National Arboretum by Oliver Freeman. Both parent species are native to Georgia and the Freeman hybrids have the attractive leaf shape, adaptability, and fast growth rate of the silver maple plus the good fall color and strong wood of the red maple. The shape of this maple is a bit more pyramidal than oval and the color is a strong red-orange. The leaves definitely drop earlier than the other cultivar.

Acer x freemanii
Considerations when using these red maples in the landscape: shallow roots mean they need a good island around them, and plant them in full sun for best color. ‘October Glory’ maples turn a more orange-red when they don’t have sufficient sun.

Parking oaks and maples are a good mix for color
Parking lot trees must be able to handle tough conditions, especially given the small spaces that trees are often forced to occupy. Between the oaks and the maples, our Georgia natives are well represented; I see also river birch (Betula) and holly hybrids (such as Ilex x attenuata). Unfortunately, non-native trees are being spec’ed into the professional landscapes too – non-native elms, pistache, and gingkos are being used more often these days, perhaps even as a reaction to the overuse of oaks and maples.

Expanding tree islands would help provide better conditions for more tree selections – fewer trees but more plant diversity would be the result. Nurserymen could experiment with more natives like hawthorns (Crataegus), American elms (Ulmus), and blackgum (Nyssa). As more and more land is developed into human spaces, using our native trees to landscape them is a small giveback that we can do to help support the insects and critters that live here with us.