Friday, November 19, 2010

Large Dogs and Small Trees

Photo0145I have a large dog and a smaller auxiliary dog. Here is a photo of the former and, yes, he is sleeping on a twin size foam mattress. This is one of the reasons I garden in raised beds. Seriously, the beds are not raised high enough to keep either dog out; the Lab can jump four feet from a standstill. However, they are very good boys and just having the beds two feet higher than the surrounding area reminds them-most of the time-it is a no-go zone. Fortunately, the Dane is too dignified to jump and doesn’t like to get his feet muddy, so my beds are safe, at least from his oversized paws.

C. j. TensanI can’t explain why someone with an affinity for preposterously large pets would have a passion for tiny trees. It’s peculiar. If you are charmed by the smallest of conifers, like I am, their best use is a space devoted primarily to them-such as an alpine bed or trough. These tiny tykes, labeled “miniatures”, tend to get lost in the mayhem of a vigorous perennial border. Even in a small bed or even a container on a balcony you can suggest a woodsy ambiance using wee conifers. This is the classic use of those hypertufa troughs you see in garden magazines.

In any vignette that is preponderantly coniferous you can ensure interest by grouping a variety of shapes. Obviously, a spreader, a globe and a cone will be far more interesting than 3 balls. Maintain scale by using the same size category in your grouping. By combining your collection with well-behaved alpines and smallerIMG_1060 perennials, you can create a bed that is beautiful and always interesting. Another plus; I might point out that conifers are the original low maintenance plant. No pruning, deadheading, staking, raking, or feeding required.

I’ve created a modified rock garden in my yard that has a variety of sizes and types of plants. It’s a work in progress as I remove what doesn’t work to make room for what does. I have used mostly dwarf conifers, but also some miniatures and a few intermediates. One key to utilizing the different sizes is to arrange them in decreasing size, from the back of the bed to the pathways or to the front of the bed. It creates a trick of perspective, reducing the difference in size through distance. In an even grander setting, you can use large garden conifers to serve as a visual bridge between towering trees beyond your garden and your smaller cultivated plants. This is an example of the design principle called sequencing.

Dwarf and intermediate conifers can be used effectively in garden borders. Remember that conifers are like teenagers; they need their space. Neighboring foliage that overlays the branches of the conifer can cause serP. o. Skylandsious damage. If you lose branches, it will never fill in; only a very few conifers such as Thuja and yew will break from old wood. Evergreens serve as anchors in the seasonal displays of the garden and provide year round structure and interest. Upright conifers of intermediate size such as the columnar Chamaecyparis lawsoniana ‘Ellwoodii’, the pyramidal Picea orientalis ‘Skylands’ or the graceful Chamaecyparis obtusa ‘Gracilis’ make outstanding vertical accents in the border.

Dwarf conifers also contribute significant color interest in the garden. Not only do they come in every shade of green from the pale spring green of new growth on firs to the deepest dark green found in the yews, but also silver, yellow, blue, purple and orange. Not to mention variegations of white, cream and yellow. Some conifers sport new growth that contrasts with the old growth creating an interesting scheme. Some bear colorful cones, notably Abies koreana ‘Silberlocke’ and Pinus pumila ‘Dwarf Blue’ (yowza!). A few conifers contribute colorful fall foliage, such as Larix kaempferi ‘Nana’.

Others, intriguingly, change color in Photo1040the winter and then return to their accustomed summer hue-without dropping their needles. Some Cryptomeria japonica that are green in summer turn almost purple in the winter. Thuja occidentalis ‘Gold Drop’ is yellow in summer and picks up orange tints in winter. Podocarpus ‘County Park Fire’ changes color from season to season, somewhat randomly and indescribably. Right now mine is sort of puce, which is a rather unfortunate sounding but interesting hue.

You can see why I’m cuckoo for conifers. Hopefully, if you were suffering from the mistaken impression that conifers were all large green amorphous cones, I’ve given you a whole new perspective on plants with naked seeds.

Tuesday, November 16, 2010

Mysterious Miniatures

J. c. Compressa

Several years ago I was working with a client who wanted a rock garden. The study and research I did in preparing to design that project kindled in me a love for dwarf conifers. Ultimately, I took the most prominent raised bed in my yard and re-imagined it as an alpine garden. That bed currently showcases 29 different dwarf conifers and I’m starting to cast my eye on two more beds that have suitable conditions.

Dwarf conifers are mysterious. There are only a few that come to us from the wild: Pinus mugo is from the Alps, Pinus pumila from the mountains of Japan and Juniperus horizontalis is native to the Eastern US. Many times, what appears to be a dwarf form in the rocky, inhospitable wild becomes a towering giant when transplanted to a well-tended garden.

C. j. YokohamaSo, what is the source of dwarf conifers? Some are selected from the seed flats of commercial growers. There can be considerable variety of color, form and growth rate when many thousands of seeds are sown. More often, dwarf and miniature forms are shoots that are taken from tight balls of slow growing ‘witches broom’ found on normal size trees. Witches brooms seem to be a result of injury or pathogen. These shoots are grafted onto cultivated root stock and frequently retain their uniqueness. They may even produce diminutive cones with seeds that reliably produce dwarf offspring.

There can be a lot of confusion when it comes to designating conifers as “dwarf”. Sequoia sempervirens ‘Adpressa’ is a choice dwarf of the coastal redwood. People are shocked when it tops out at about 75 feet tall, but  the species gets 300 feet tall. At its broadest, the definition of a dwarf conifer is “one that fails to attain the size and stature of the parent plant.” For my purposes, it has to stay a lot smaller than that! The American Conifer Society is recommending that these be called “garden conifers” as opposed to “dwarf conifers” in an effort to alleviate some of the confusion. In addition, the ACS has adopted the following four size categories for conifers:


Growth per year

Size at 10-15 years


less than 1 inch

1 foot or less


1-6 inches

1-6 feet


6-12 inches

6-15 feet


more than 12 inches

more than 15 feet

C. l. EllwoodiiUse caution when selecting your dwarf conifer. Names can be very perplexing and tend to be confused in the trade. For example, there is a group of Chamaecyparis lawsoniana labeled ‘Elwoodii.’ C. l. ‘Elwood’, a lovely blue pillar, may reach 15’ tall and 5’ wide. C. l. ‘Ellwood’s Pillar’ looks identical in the pot but matures at 4’ tall and 15” wide. There is also ‘Ellwood’s Pygmy’ (2’ tall), ‘Ellwood’s Nymph’ (12 feet tall) and several others. Ellwood was a busy guy.

P. a. Little GemMake sure the plant you want to purchase is indeed slow-growing. It should have short internodes, which will show that it is growing at the Miniature-Dwarf rate. An open, loose structure indicates a faster growth rate. Slower growing plants tend to be expensive but not as expensive as buying a plant that quickly outgrows its space and must be replaced.

In addition to categorizing the size of conifers, the ACS also defines shapes. Many people expect a conifer to be conical, like a classic Christmas tree. Conifers, especially dwarf conifers, come in many different shapes with exciting design possibilities:

  • Globose: globe-like or rounded in general outline.
  • Pendulous: upright or mounding with varying degrees of weeping branches.
  • Narrow upright: much taller than broad; includes fastigiate, columnar, pyramidal or conical.
  • Broad upright: includes all other upright plants with do not fit into categories 1-3.
  • Prostrate: ground-hugging, carpeting plants without an inclination to grow upward.
  • Spreading: wider than tall.
  • Irregular: erratic growth pattern.
  • Culturally altered: pruned or trained into formal or imaginative shapes, such as standards. T. c. Stockman's Dwarf

Texture varies widely between and even within species. Hemlocks have short needles, Pines are quite long. Fir needles are stiff. Some Chamaecyparis have soft, touchable feathery foliage, others have stiff fans. Some conifers are loose and open, others tight, congested and dense.

Dwarf conifers provide continuity through the seasons and contribute an incredible variety of form, size, color and texture to the garden-even in the snow. Flowering plants will come and go but conifers will endlessly delight you.

Wednesday, November 10, 2010

Coniferous Splendiferous

I live in the Evergreen State. Our state tree is the Western Hemlock. We have over 30 native conifers including varieties of Juniper, Cypress, Cedar, Fir, Spruce, Yew, Hemlock, Redwood, Pine, and Larch. There is little wonder that I am fascinated with these sturdy and beautiful botanical stalwarts.

There are a lot of misconceptions about conifers. Did you know that not all conifers are needled nor do all of them bear classic, brittle, scaled cones? However, one thing is true of all coPhoto1028nifers: they belong to a class of plants that bear naked seeds as opposed to the rest of seed bearing plants whose seeds are enclosed in ovaries. The class is Gymnospermae and contains three botanical orders: Coniferales which typically bear classic cones; Taxales, which includes the yews, bear less recognizable “cones”; and Ginkgoales which, obviously, is the classification for Gingkos -the only broadleaf plant in the class Gymnospermae.

Conifers may be single trunked or multi-trunked. Most, but not all, conifers are evergreen. Larix (larch) are the most common deciduous conifers and, like Ginkgos, typically have colorful foliage in the fall. The immature cones are the “flowers” of the conifer. Most bear both male and female cones but a few, like yews and junipers, are dioecious. Yews and junipers are also different in that they carry their seed in structure that is botanically similar to what we would recognize as a cone, yet more resembles a fruit.

The female cones have two types of scales; the outer is sterile and protective, the inner scales hold the seed. It can take up to three years for the seed to mature. Some conifers require heat, such as a forest fire, in order to disperse their seed. The ripe cones may be carried for 20 years before fire releases the seed to drop onto a bed conveniently cleared of competitive plants.glaucous

In the wild, conifers often live in poor, dry soil and sometimes summer drought, though firs and hemlocks tend to prefer cooler climes and consistent moisture. For an especially low water use area, choose pines or a conifer with glaucous foliage. The blue shade results from a waxy coating that inhibits moisture loss. Generally, conifers for the garden want to be planted in well-draining soil that is amended with some organic material. Avoid low spots and don’t position soaker hoses directly over roots. Most conifers are petulant about wet feet and will drop needles and look scruffy in that environment. Taxodium are an exception; commonly referred to as swamp or pond cypresses,they can be found growing natively in standing water. To a lesser extent, Larix and Thuja are somewhat tolerant of poorly drained soils.

The best time to plant conifers is: not summer. Planting them in autumn through early spring will give them a chance to adapt before the summer stresses hit. Make sure to untangle any circling roots and that you do not plant it too deeply. Even if your new conifer will be drought tolerant, it will need consistent water during the first summer.

C. d. KnaptonensisAlthough conifers generally prefer full sun, some of the variegated versions, especially the Cryptomeria, appreciate some shade. Also, Taxus and Chamaecyparis will tolerate some shade. Conifers need their space and will sulk if crowded. Branches will drop needles or even die if overlaid with neighboring foliage. Some needle drop is normal although most conifers don’t replace their needles each year like deciduous trees. Needles may last from 1-3 years, but eventually they drop; this is sometimes called “flagging.” As long as the new growth is strong, lost needles from old growth should not be concerning.A. l. Arizona Compacta

Conifers tend to be quite sturdy if not stressed. Notable stressors include poor drainage, air pollution, damage to roots or to bark and soil compaction. Give your conifers a suitable situation and they will give you year round, season spanning structure and beauty. It’s an excellent exchange.