Sunday, February 28, 2016

Buds Poised

Coral honeysuckle (Lonicera sempervirens)
Early signs of spring are showing. The Hepatica bloomed and the trout lily blooms (Erythronium umbilicatum) are starting. A few red maple flowers are to be found as well and yesterday I saw a large patch of the annual bluets (Houstonia pusilla) in full bloom.

Most people don’t notice these things; the big show is yet to arrive. While we wait, I enjoy noticing the swelling buds of trees and shrubs.

While some buds look the same as they have all winter, others are noticeably growing larger. In some cases, like the spicebush (Lindera benzoin), the color reflects the color of the flower because it is the flower bud that you are seeing. The Chickasaw plum (Prunus angustifolia) gives a hint of the white flowers yet to come.

Spicebush (Lindera benzoin) flower buds

Chickasaw plum (Prunus angustifolia)

Aesculus pavia

Sometimes the flowers are inside the leaves, like the red buckeye (Aesculus pavia). I can usually tell which buds will have flowers because they are so much larger, but sometimes I get fooled and the bud opens with only leaves.

Viburnum and azalea (Rhododendron) buds are similar in that regard as well – bloom buds are noticeably larger (and they don’t even contain the leaves!).

Crabapple (Malus angustifolia) leaves
Keep an eye on your shrub and tree buds and watch them expand as the days get longer. Earlier blooming plants usually start first. You might even find it interesting to keep a journal of the changes.

Phenology is the study of plant life cycle events and how they change over time due to climate. Are certain plants blooming earlier now than they were 10 years ago?

Well, whether they are or not, it’s always interesting to notice and appreciate how much nature can pack into that tiny bud package. 

As for that honeysuckle in the first picture, it's been blooming all winter. Another flower was blooming just a few feet away.

Coral honeysuckle (Lonicera sempervirens) blooming in February

Sunday, February 21, 2016

Alternate or Opposite

When I’m talking to people about plant identification, leaf arrangement is the first place that I start. And while I’m usually talking about woody plants (trees, shrubs and vines), leaf arrangement on perennials is used for identification as well. To simplify the concept, this post will focus on woody plants.

Calycanthus floridus, opposite leaf arrangement
Leaf arrangement on a plant is either opposite or alternate: leaves may be opposite one another on the stem or they may be alternate along the stem.

Occasionally you might find plants with leaves arranged in a whorl, which is 3 or more leaves together. Lily (Lilium) is a good example of a plant with leaves in a whorl.

Viburnum with opposite twigs

In the winter time, you might think that you can’t discern leaf arrangement on deciduous plants because the leaves have dropped. The clues are still there, even when the leaves are gone. In younger trees or shrubs, you can study the branches – they follow the same pattern as the leaves. Older trees might not have all their original branches so it’s best to examine the twigs.

The twigs are the ends of the branches; they represent the most recent year’s growth. In a slowly growing plant, the twig might be very short, but in a rapidly growing plant there could be several inches of twig. The fresh growth on the twig is a good place to check for leaf buds.

Hawthorn (Crataegus) leaf buds, alternate

Leaf buds are next year’s leaves. They may be large and prominent like American beech (Fagus grandifolia), or they may be so small as to appear hidden like sweetshrub (Calycanthus floridus). In both cases, you can still discern the arrangement.

Most leaf buds are large enough to see in the winter. You will usually see the leaf bud and below it is the leaf scar (where last year’s leaf was attached). Only occasionally do I feel the need to use a 10x hand lens to figure out arrangement. Another tip: twigs with opposite leaf arrangement are fairly straight while those with alternate leaf arrangement might have a bit of a zigzag appearance.

Beech leaves, alternate
Leaf buds are not visible in the spring and summer because they haven’t formed yet, but it doesn’t matter because we have the leaves to help us to see the arrangement. Occasionally some leaves are missing, so look carefully before you decide the arrangement is alternate; it might be opposite with missing leaves.

Now that you’ve identified the leaf arrangement, you can proceed further into identifying the plant. Most plants have alternate leaf arrangement, so if yours has opposite then you have a smaller set of choices.

I’ve given up on using mnemonics to remember the common opposite plants; every version I’ve heard leaves several of them out. Here are the common ones in Georgia: maple (Acer), buckeye (Aesculus), Viburnum, ash (Fraxinus), dogwood (Cornus, except one species is alternate), elderberry (Sambucus), fringetree (Chionanthus), beautyberry (Callicarpa), Euonymus, honeysuckle (Lonicera), sweetshrub (Calycanthus), and buttonbush (Cephalanthus).

Most identification books offer a “key” for you to follow. The key walks you through a series of questions until the plant is identified. Winter keys will focus on other twig characteristics such as leaf scars, bundle scars, terminal bud and bud characteristics and presence of lenticels (you might want that hand lens here). Summer keys will focus on the leaf characteristics as well as flowers and fruit (seeds, nuts, berries).

I always recommend that the best way to learn is to practice on plants that you already know until you are familiar with the keying process.

Good resource: Native Trees of the Southeast by Kirkman, Brown and Leopold (older version of this book is Trees of Georgia and Adjacent States).

Sunday, February 14, 2016

Native Shrubs for Supporting Birds

Lots of blog posts out this week about watching birds in the winter, and this weekend is also the Great Backyard Bird Count. My feeders are out during these lean months, and this week’s second snow “event” of the year had them flocking in to devour seeds, suet and mealworms. I like to feed them in the winter because I know that humans have taken more natural winter food sources than we should have.

Cardinal with Euonymus americanus
In my continued focus on shrubs, I’d like to offer some ideas on native shrub choices that we can make in Georgia to provide year-round bird support. These ideas might be of particular interest to people that have a passion for birds and want to include their garden as a way of supporting them.

There are 3 areas of support that I would consider for birds: shrubs that provide fruit, berries or seeds for birds; shrubs that provide dense cover; and shrubs that support insects that would then be a food source for birds.

Food for Adults

Shrubs that provide fruit, berries or seeds are basically supporting adult birds. Adult birds that eat fleshy fruits or berries are frugivores. Adult birds that eat seeds are granivores. Some granivores like cardinals will also eat berries in the fall in winter.

When selecting these shrubs, be sure to research their light preferences. A shrub that grows in too little light won’t produce as many flowers and, consequently, not as much fruit/seeds. Your success in providing food for birds with these shrubs depends on your placement of them.

Here are some ideas: Native viburnums (Viburnum spp.), hearts a bustin’ (Euonymus americanus), spicebush (Lindera spp.), elderberry (Sambucus spp.), holly shrubs (Ilex verticillata, I. glabra, I. vomitoria, I. cassine), chokeberry (Aronia spp.), shrub dogwoods (Cornus amomum, C. foemina and others), St. John’s wort (Hypericum spp.), beautyberry (Callicarpa americana), blueberry (Vaccinium spp.), huckleberry (Gaylussacia spp.), buttonbush (Cephalanthus occidentalis), sumac (Rhus spp.).

The fruits of silky dogwood (Cornus amomum)

Cover for Birds

Dense shrubs have a thick network of branches inside the shrub. They are the ones you hesitate to stick your hand inside when the tennis ball you threw for the dog rolls into it. Twigs and branches are going every which way! Those shrubs are perfect places for birds to build a nest or just take shelter during the night.

Some ideas:  Some native viburnums such as V. obovatum and V. prunifolium. Shrubby hollies like Ilex vomitoria and Ilex glabra. Dwarf forms of wax myrtle (Morella cerifera). Aggressive pruning can encourage dense growth, even of shrubs that might not have been so inclined.

Viburnum obovatum

Shrubs as Larval Host plants

A third source of support for birds is to provide them with insects. Most birds (96%) feed insects to their nestlings and many adult birds eat insects as part of their diet (insectivores). The ability of plants in our landscapes to both attract and produce insects is an important point when selecting plants.

Azalea sphinx moth in my garden
An important source of information in understanding which plants have host relationships with insects is a study and subsequent book published in 2007: Bringing Nature Home by Doug Tallamy.

A website now makes the data from the study available to all of us. Based on that data, here are the genera which have shrubs (some also have trees) and the number of insects that use them as hosts:

Cherry/plum (Prunus, 456 different insects), blueberry (Vaccinium, 288), blackberry (Rubus, 163), hawthorn (Crataegus, 159), alder (Alnus, 156), rose (Rosa, 139), dogwood (Cornus, 118), viburnum (Viburnum, 104), currant (Ribes, 99), spirea (Spiraea, 89), and sumac (Rhus, 58).

You can see there is some overlap - some plants that provide fruit for birds are also good at being a larval host. It would be a good opportunity to choose something that is in both lists, especially if you have a smaller area. For more ideas besides shrubs, visit my earlier blog on Natural Bird Food.

Sunday, February 7, 2016

Native Shrubs for Small Gardens

Fothergilla 'Mount Airy'
Yards are getting smaller. They were already small in many urban areas, but now even suburban homes are being built on ¼ acre lots. Those landscapes can still use native plants and be rich in plant diversity, by planning for it. When it comes to choosing woody plants, you’ll want to look for smaller plants to accommodate the smaller landscape.

Using several smaller shrubs - instead of 1-2 big ones that have to be pruned often – gives you more manageable plants and allows for increased plant diversity. Fortunately there are dwarf forms of many native shrubs to use in smaller spaces:

  • Virginia sweetspire (Itea virginica) ‘Little Henry’ gives mounds of late spring flowers and great fall color.
  • Oakleaf hydrangea (Hydrangea quercifolia) ‘Pee Wee,’ ‘Little Honey,’ ‘Munchkin,’ ‘Ruby Slippers,’ and ‘Sikes Dwarf’ provide big leaf texture in a smaller form.
  • Fothergilla ‘Mount Airy’ and ‘Blue Shadow’ are hybrids between the two species (F. major and F. gardenii) and are slow growing enough that they could be kept lightly pruned to a smaller size. ‘Blue Mist’ is a small cultivar of F. gardenii.
  • Summer-blooming summersweet (Clethra alnifolia) has dwarf forms in ‘Hummingbird’ and ‘Sixteen Candles.’ This shrub is tolerant of wet soils and blooms during June-July.
  • Evergreen yaupon holly (Ilex vomitoria) has long had cultivars ‘Nana’ and ‘Stokes Dwarf’ for that mini-meatball look, but try not pruning it for a softer dome-like shape. It’s a great dense shrub to provide cover for birds.
  • Another twiggy cover for birds would be a wax myrtle cultivar such as Morella cerifera ‘Don’s Dwarf.’ At 3-5 feet in height/width, it may need some light pruning to stay smaller. 
  • Another evergreen choice is mountain laurel (Kalmia latifolia) which has been bred for medium sized cultivars like ‘Olympic Fire,’ ‘Sarah’ and ‘Pristine,’ as well as super small ones like ‘Elf.’
  • A smaller evergreen for shade would be a cultivar of Florida anise (Illicium floridanum) such as ‘Pebblebrook’ or the variegated ‘Shady Lady.’
  • Pipestem (or hobblebush) is a Coastal plain native (Agarista populifolia) and ‘Leprechaun’ is a wonderfully adaptive evergreen dwarf form.
  • Want some colored foliage? Try ninebark (Physocarpus opulifolius) 'Little Devil' or 'Tiny Wine' for burgundy accents.
Clethra alnifolia 'Hummingbird' in July
Hypericum frondosum

In addition, there are woody perennials, sometimes called sub-shrubs, that you can use.

While some of these appear to be what you might call a perennial, they have woody or persistent stems: salvias like Salvia greggii, Georgia calamint (Clinopodium georgianum), St John's wort (including Hypericum frondosum 'Sunburst', 'Blue and Gold' plus others) , New Jersey Tea (Ceanothus americanus), the herb-like dittany (Cunila origanoides), Georgia beargrass (Nolina georgiana) and Yucca.

Red buckeye (Aesculus pavia)

Need a small tree? Consider using a large shrub instead: red buckeye (Aesculus pavia), native azaleas (such as Rhododendron canescens), fringetree (Chionanthus virginicus), blackhaw viburnum (Viburnum prunifolium), and winterberry holly (Ilex verticillata).

All of these can be carefully pruned to mimic a tree form while still being smaller than an actual tree.

How can you get even more diversity in a small landscape? Reduce the lawn and borrow from your neighbors.

  • Reduce the lawn by re-evaluating how you use it. Often people stop actively using lawn for playing but forget to actually downsize the amount of room it takes. Sometimes it is takes up some of the sunniest areas in the landscape – prime territory to reclaim for blooming plants!
  • Borrow diversity from your neighbors – do they have maples and birches? Plant something else in your yard then. The maples and birches in their yard will be as close as if they were in your own yard.

Remember to consider these as suggestions and research the plant names given to see what would be appropriate for you. Consider light requirements (sun/shade) as well as the moisture level (wet/dry) between your space and what the plant prefers (or tolerates).