|
Home Feature Articles Bug Book Plant Gallery Library Gardener's Seed Charts & Formulas About Us |
|
|
|
|
Introduction - Conifers have and always will be a staple in the landscape, in the past, the present and in the future. Many of the older homes one sees will probably have an old conifer in the yard somewhere, in fact it not unusual to see older homes with massive old spruces or pines in the front yard blocking the sidewalk and in some cases towering over the whole house. That was then, when people didn't know or ignored the fact that these plants would get so large and just maybe adopted the attitude that they would just take care of the plants size by pruning it each year, but of course we know that didn't last long. Today there are still homes with conifers, but people have gotten a little smarter and have come to realize that they can have a conifer in their front yard like mom and dad, but they won't have to worry about it getting out of hand. Back then the average homeowner had little interest in dwarf plants, but today people are looking for plants that are low maintenance, those that fit into the small urban landscape and won't outgrow their intended locations and for something different and unusual. Those plants are the 'dwarf conifers' and in the last twenty years or so they have become increasingly popular. With hundreds upon hundreds of cultivars available, there is a conifer to fit any need. Many of the cultivars available are the compact, dense and symmetrical forms that many people can relate to, but for those with a taste for the unusual, there are forms that weep and creep and those that have unusual foliage and branching habits. There are also a wide range of foliage to choose from, with colors from greens, to blues, to golds and even variegated forms. They may not all be available in all areas, but the selection that is available in the marketplace should be enough for the average homeowner. Of course for the collector, the real connoisseur, even the largest selection is sometimes never enough.
WHAT IS A CONIFER - Most people tend to think that all conifers are evergreen trees and to a point this is true. The name conifer is derived from the Latin "conus" meaning cone and "ferre" meaning to bear, in other words conifers are those plants that bear cones or that are cone bearing. Pines, spruces, hemlocks and firs, etc. are classic examples of those trees which are evergreen and bear cones, but there are several species of trees that are deciduous that also bear cones, these too are considered to be conifers, the deciduous conifers. They include Ginkgo, Larix, Metasequoia, Pseudolarix and Taxodium. All conifers belong to the division Gymnospermae, which means all conifers are gymnosperms. A 'gymnosperm' is defined as a plant that has seeds that are naked, that is, the seeds are not enclosed in an ovary or structure that surrounds the seed. Plants with surrounded, or enclosed, seeds are called 'angiosperms', such as apples, plums, peaches and even oaks, whose seeds are enclosed in an acorn. A gymnosperms seeds are born somewhat in the open, they are usually settled into the crevices of a holding structure, which we commonly call a 'cone.' The flowers of conifers are so untypical of most flowering plants, that many people don't think of them as having flowers at all. Their flowers are usually inconspicuous and basically consist of the essential reproductive organs and are enclosed in the cone. Male and female flowers are produced separately, when they are produced separately, on the same tree, they are considered monoecious and when they are produced on different trees they are considered dioecious. The male flowers are comprised of a number of stamens, arranged in catkin-like clusters. The female flowers are born in cones, each flower usually consisting of a bract which is sterile and a fertile scale that produces one or more seeds on its axil. The yew (Taxus species) is the only conifer that does not develop cones, but instead, a fruit-like berry that does not totally surround the seed. What is the difference between a Variety, Form and Cultivar? The terms variety and cultivar seem to be the most confusing to people and in practice the term variety is often used synonymously with the term cultivar. The natural variations in plants of the same species are very difficult to separate into precise categories. It is these small but sometimes significant differences between plants of one species, such as shape, color or the number of leaves, that give rise to the smaller subgroups called varieties. The difference between a variety and a cultivar is, that a variety is a subdivision of a species or a group of plants within a species, that has unique characteristics that occur naturally. A cultivar is a 'cultivated' variation of a variety. A variety can usually be reproduced both asexually (cuttings, grafting, layering) and sexually (they generally come true from seed, at least to a very high percentage). The variety name is written in Latin and is written with a small first letter. It is sometimes, but not always preceded by the abbreviation (var.) for variety. Example: Pinus mugo var. mughus Pinus mugo mughus - mughus is the variety of Pinus mugo -- It can be written either way The term form or forma is also a subdivision of a species, ranking after variety. It is used to designate minor and sporadic variations within the variety such as differences in the color of the flower, fruit or leaf shape. A form will generally not come true from seed and vegetative propagation is necessary to maintain its variation or particular characteristic. When a form is designated, the word form, forma or the letter 'f.', will precede the name of the variety. The term 'form' is seldom used or seen written in horticultural literature and plant catalogs and is most often used by botanists and taxonomists but we mention it here so that you will know what it represents if you do come across it. Example: Picea pungens f. glauca --- glauca is the glaucous (or blue) form of Colorado Spruce known by its common name as - Colorado Blue Spruce Example: Picea omorika f. pendula -- pendula is the pendulous (or weeping) form of Serbian Spruce known by its common name as - Weeping Serbian Spruce The word cultivar is a contraction of the words "cultivated" & "variety". A cultivar is defined in the International Code of Nomenclature of Cultivated Plants as "an assemblage of cultivated plants which is clearly distinguished by any characters (morphological, physiological, cytological, chemical or others ), and which when reproduced ( sexually or asexually ), retains its distinguishing characters". A cultivar is a unique group of plants that must be artificially maintained by human efforts or they would cease to exist. Cultivars can arise from within a species or as a hybrid between one or more species. A cultivar name will consist of a non-Latin, proper name that can be recognized by horticulturalists worldwide and one that does not confuse its identity with that of other cultivars. (Such as Chamaecyparis obtusa 'Rigid Dwarf' - this is an example of a cultivar with a common cultivar name.) An exception to this may be cultivars that were named before January, 1, 1959, some of these have retained their Latin cultivar name. ( An example of this is Chamaecyparis obtusa var. tetragona 'Aurea' - 'Aurea' is the Latin cultivar name.) Most cultivar names begin with a capital letter (except for some rare exceptions) and are either in single quotes or preceded with the abbreviation (cv.) for cultivar, but not both. A cultivar name can be attached to the species name, the common name or to the variety, as with the example above. In some instances, especially when cultivars are of a hybrid or unknown origin, their names can be assigned directly to the genus.
WHAT IS A DWARF CONIFER AND HOW DO THEY ORIGINATE - Obviously, dwarf conifers are those conifers that stay dwarf, that is to say, their mature size is smaller than that of the species. This is not to say that a dwarf, of a species will retain the original shape of the species, but only remain smaller, some do, (such as Picea abies 'Remontii' and Chamaecyparis obtusa 'Gracilis') but many dwarf conifers are variations of the species and can grow in a variety of shapes from buns to globes, to upright irregular, to low and creeping or upright and weeping, some even develop into unusual, contorted forms. The dwarf sizes or even the unusual growth habits found among dwarf conifers can result from any number of reasons. They can originate as a seedling variant, which can be found growing in the wild or in a nursery seed bed. As a rule seedling variants generally retain their dwarf and/or unusual growth habit. They can also be found growing as a bud mutation, otherwise known as a "sport" on a species or a cultivar. These so called sports are generally and sometimes distinctly different in color and foliage type and when propagated vegetatively, they will normally maintain their unusual characteristic, however they could easily revert back to the species or cultivar from which they originated if they are not looked after. When a reversion is noticed, however, it should be cut out. And finally a third way dwarfs can originate is from a 'witches broom'. This type of mutation is nothing more than a densely congested mass of foliage found growing on a plant, which may occur as a natural cell mutation (sport) or it can be caused by insects, such as feeding mites or parasites such as fungi, bacteria and viruses, but regardless of the cause, plants propagated from these brooms are always likely to revert, by producing normal growth, which must be removed as soon as possible before it overgrows the dwarf. Many of the dwarf spruce and pine cultivars in existence today have originated from witches brooms.
HOW FAST DO DWARF CONIFERS GROW - WHAT GROWTH RATE CAN BE EXPECTED - HOW LARGE WILL THEY GET - Dwarf conifers are generally slow growers (that is in relation to many other plants), but their growth rate can vary from one kind of plant to another and even for the same plant when it is grown in different climatic regions, even cultural conditions can influence their growth rate . The American Conifer Society has established a relative guideline for classifying plant sizes and habits, with growth rates, these rates should not be interpreted as "written in stone" for any given plant, they are merely guidelines. For instance, a conifer may be listed as growing 3"-6" per year, but under less than optimum cultural conditions or in different climate regions, that particular conifer may only grow 1-3" per year. The guide according to the American Conifer Society is as follows:
Planting: Conifers, dwarf or otherwise should be transplanted in the spring before new growth starts or in late summer/early fall after the seasons growth has hardened up and matured. Unless they have been purchased in a container (in which case they can be planted at most any time), they need to be moved balled and burlaped, that is with a ball of soil on their roots, since their roots should never be allowed to dry out, nor should the roots be exposed to the sunlight for even a brief time. The principle reason for this is the symbiotic relationship between the fungus 'mycorrhiza' and conifers. The mycelium (the underground vegetative parts of the fungus) affixes itself to the roots of conifers and acts like root hairs that assist the plants in absorbing nutrients from the soil. It does not act as a parasite, but as a beneficial partner to the plant. This type of relationship has long been known with other plants as well, such as Rhododendrons, Kalmia and Epigaea repens (Trailing Arbutus). This root fungus is more sensitive to sunlight and drying, than the roots themselves and it is but one more reason to be careful when moving and planting conifers. Soils & pH - The ideal soil for most conifers is a moist, well drained, sandy, clay loam, slightly on the acidic side, with the emphasis on 'well drained'. The majority of conifers will require a soil that is neither too wet or too dry, one that is capable of retaining a consistent moisture content for the plant. Soils such as this often contain just the right amount of humus (organic matter.) Conifers appreciate the addition of organic amendments such as peat moss, leafmold, compost or animal manures worked into to the soil prior to planting and used as a top dressing from year to year. Not only will this practice maintain those soils that are already ideal, but it will greatly improve those soils that are either too sandy or a bit on the clay side, aiding in better water and nutrient holding capacity, while helping to provide adequate and proper drainage. Best of all, with a good soil, you can be assured of growing vigorous, healthy plants. While the majority of conifers prefer these ideal soil conditions, there are a few that can adapt quite well to soils at either extreme. Nearly all of the Junipers and many of the Pines, actually prefer a soil that is not too rich, but poorer and dryer. Once they have become established they will adapt and do quite well in these less that ideal soil conditions. For that matter many of the Junipers and Pines will also adapt well to heavy clay soils, as well. Arborvitae and Japanese Cryptomera will also adapt well to heavy clay soils. Although not many conifers are swamp lovers, a few species come close and will grow in wetter than normal soils, these include the Atlantic White Cedar, balsam Fir and of course Arborvitae. It seems as though the Arborvitae will grow in just about any soil conditions and the fact is, it can! While it prefers the 'ideal soil', like all the other conifers, and it can adapt to moist, wet or heavy clay soils, believe it or not - once established this plant is also very drought tolerant. The pH of the soil will have some bearing on whether your conifers will be vigorous and healthy. If the pH is to either extreme they may begin to suffer from nutrient deficiencies of some kind. Most conifers prefer a pH range somewhere between 6.0 (slightly acidic) to 7.0 (neutral). Although many prefer a slightly acidic soil, there are a surprising number that are quite adaptable to either acidic or alkaline soils, as long as it is not to either extreme. In fact, some of the conifers that you might not think would grow well in alkaline soils include several kinds of Junipers (Common, Chinese, Savin), Scots Pine, English Yew and, you guessed it - American Arborvitae. Now didn't I tell you that Arborvitae was one tough cookie? Light Requirements - The light requirements of dwarf conifers, in most cases, will be similar to the species from which the plant originated. Most prefer full sun, and many will do well in a filtered sunny situation, but still there are many that although they seem to be maintaining themselves in filtered sun, actually resent it and will perform much better in full sun. Some of these include arborvitae, juniper, pine and larch. Hemlocks and Taxus are about the only conifers that are best reserved for a brightly filtered sunny situation to full shade. Although it is suggested, with hemlocks, that with adequate moisture, they can be placed in full sun, they will always look better out of full sun. Hemlocks, including their dwarf forms, are also highly susceptible to wind and sunscald. Note: A word about colored and variegated dwarf conifers. Many dwarf conifers are green and shades thereof, but there are just as many, if not more, that are variegated or have foliage colors other than green. There are various shades of blue, blue/grey, grey/green, gold, yellow and those that are multi-colored. Some of these multi-colored conifers are heavily variegated and can be very focal, while with others, you need to be up close to the plant to appreciate its variegation. Regardless, just about all of the colored or variegated dwarf conifers will require an adequate amount of sunlight in order to maintain their coloration. When colored or variegated plants are not given an adequate amount of light, they will begin to lose their color or variegation. It is even possible for them to revert back to the color of the species, if this should happen and they are given an increase of sunlight, the color or variegations should return. A good example of this is Chamaecyparis pisifera filifera aurea (Gold Thread Cypress), when this plant does not receive adequate light, it will loose its brilliant gold color and look more green than gold. There could be other reasons for a loss of vivid color, such as soil conditions, wind, disease, etc. but inadequate light is usually the common culprit. One just needs to keep an eye on their plants, and take notice of these types of changes. There are even some conifers, whose foliage will burn or fade, if given too much direct sun, these are often some of the gold leafed cultivars, such as Chamaecyparis obtusa 'Crippsi'. Climactic Conditions - When choosing and placing conifers in the landscape, all of the basic cultural conditions must be considered, such as light, soil type, soil moisture, etc. but the type of climate, in which each species grows best, should also be taken into consideration. For instance, Firs, many of the Chamaecyparis species, Pseudotsuga and even Hemlock will all grow much better in areas with high atmospheric moisture. Moisture rich, coastal mountain ranges, or inland valleys that have abundant rainfall are the native habitat of many conifers, even the moist atmospheric conditions created within dense forests, can create these ideal growing conditions. This is not to say that these conifers will only grow in these conditions, many are quite adaptable to drier regions, it is only another point to consider, when choosing these plants as they may require a little more diligence on your part to keep them looking their best. Many of the firs, spruces and hemlocks do make good landscape plants and are grown and used throughout most regions of the country, but best growth will be obtained in cooler zones as they resent hot, dry summers, long periods of drought and areas with air pollution. On the other hand conifers, such as Cedrus libiani, require and will only flourish in areas with a mild climate and dry atmosphere, and many of the pine and juniper species can be found as natives, growing in the hot and harsh central plain regions. Conifers, like all other plants, have their areas of origin and optimum growth will occur in areas that match their native habitat, but like all other plants, many are adaptable to a wide range of conditions, as long as they are not to either extreme. A diligent gardener can often have success with many different species, regardless of their region of origin. It is just a good thing to know and consider. Many of the dwarf conifers are fairly drought tolerant, that is once they are established. This is especially so of the Japanese cedar, junipers, blue spruce and several pine cultivars, but as with any plant, in times of drought, they will benefit from a drink of water. They will not need to be watered everyday, but a good soaking every week or two, when rain is lacking, will help to keep them looking their best. Besides this, the most critical times for watering are when a plant has just been planted, or transplanted, so that a good root system can be established, and a good soaking just prior to winter, helps to prevent desiccation. (Desiccation occurs when a plant uses up its moisture reserves and doesn't have enough moisture within its leaves, stems, roots, etc. to replenish itself. It can occur in the growing season during periods of drought or in areas with constant wind during the winter months.) Over winter damage from desiccation is a common occurrence with conifers and broad leafed evergreens, that is why it is important to water plants well before the ground freezes and winter is upon us. Feeding - Should you fertilize your dwarf conifers? When they are first planted, the addition of a high phosphorous , granular fertilizer, such as super phosphate (0-20-0) or a more complete, low nitrogen fertilizer, such as (5-10-5) or (5-10-10) mixed at 1/2 the recommended rate into the back fill, will usually be sufficient to help the plant become established. In general though, dwarf conifers require very little fertilization, in fact when they are fertilized regularly or abundantly, they put on greater than normal growth which ultimately leads to plants that are spindly, this is especially so with the pines, where excessive growth can produce large gaps between the whorls of branches and foliage. If you feel you must feed your plants, well decomposed organic matter such as rotted manure, leafmold, or compost would be the most effective or a bark mulch applied seasonally will not only maintain moisture, but supply humus as it breaks down. If you have plants that are already established and you are one of those 'fertilizer happy' people, that feel the need to fertilize everything in sight, you should use a little slow release fertilizer such as osmocote, but even then at only 1/2 the recommended rate. Mulching - There are several good reasons for mulching plants and for dwarf conifers it is the same as any for other plants. Mulching not only sets off the plant and makes it look more attractive, but it also helps to maintain soil moisture and keep the root system cool while keeping down weed growth. In the winter months it also helps to insulate the root system of the plant. Organic mulches such as bark, leaves, leaf mold, etc. are much more beneficial to plants than inorganic mulches such as stone, gravel, lava rock and the like which are basically more decorative than anything else. Organic mulches, as they break down will provide some nutrients to the plants or at the very least, help to improve the soil texture over time or just help in maintaining an already good soil. Whatever type of mulch you decide to use, always remember, that the composition of the soil in which your plant grows is more important than the mulch you place above it. If you plant a conifer in a soil type that it does not grow well in, no amount of mulch will help it to grow better.
Dwarf conifers are subject to the same insects and disease as the species from which they originated. Although conifers are subject to a large number of insects and disease, (some more than others), when they are growing under proper cultural conditions they are seldom troubled significantly. In fact, when any plants are not given the conditions they require for optimum growth or when they are placed under stress for any reason, for extended periods of time, insects and disease will ultimately become a problem. Because many dwarf conifers have foliage that is dense and compact, air movement through these plants is almost nonexistent and due to this type of branching habit certain dwarf conifers, such as Picea glauca 'Conica' (Dwarf Alberta Spruce), are highly susceptible to spider mites, especially in hot, humid weather. A non-chemical preventative measure for mites is to hose the foliage of your plants down with a forceful stream of water every week or so when weather conditions become ideal for these pests. For chemical control, one must spray a proper miticide or contact insecticide, hopefully before too much damage has resulted. Pruning - Pruning is often not a consideration when choosing dwarf conifers, due to their general slow growth and compact habits. This should hold true, especially if one has chosen their plant properly and put it in its proper place in the landscape, but unfortunately this isn't always the case. If you choose the wrong cultivar and plant it in the wrong spot you will find that at some point you will have to prune it. If this is the case care must be taken because the character of a particular variety and the way it was meant to grow can sometimes lost, either by severe pruning or shearing or by an inexperienced pruner. As always, there are exceptions, some dwarf conifers can be cut back hard, only to fill in with cleaner more decorative foliage, such is the case with Chamaecyparis obtusa 'Filicoides. In some instances this hard cut will suffice for two or three years or more, but with other more aggressive growers, it will mean that once you find yourself pruning a fast growing conifer, you may have to prune it yearly to maintain a desired size. For some people this may be fine, but aren't you undermining one of the reasons a 'dwarf conifer' was chosen in the first place, low maintenance and little or no pruning? Although some dwarf conifers might normally grow only a few inches per year under average growing conditions, they sometimes may outgrown their intended location due to excessive fertilization or increased water or light, in which case it's time to move the plant or start to prune. If your plant has an aggressive habit of growth you may be better off moving it. Some dwarf conifers are not dense and compact, but naturally grow loose, open, or irregular, these will only require pruning should one decide to alter their natural shape and growth habit, while others will need a little help in the early years to get a nice compact habit going. Even still there will be some of those magnificent old specimens that will require some selective pruning to maintain their architectural grandeur. All in all many of the dwarf conifers when left on their own, will live for many years without a blade ever being put to them. How can Dwarf Conifers be used in the landscape - Dwarf conifers can be used in much the same way as many other types of plants, for foundations and borders or in creating island beds. Many make good specimens, accents or focal points, while some of the larger, more symmetrical ones can be used to create an evergreen background. Those with unusual textures and colors can be integrated among trees, shrubs, groundcovers, perennials, etc. providing a contrasting effect to brighten up a dull landscape. Dwarf conifers make ideal plants for urban gardens where landscape areas are small or space is limited. For larger gardens, they are often used in creating an Oriental or Japanese style garden, or used in the rock garden where many seem to fit in so naturally. To a collector, they are often used to create a 'conifer garden' to display a variety of shapes and forms and to show off the owners prized collections. They even make good plants for commercial landscapes where some kinds, such as Birdnest Spruce or many of the Juniper varieties, can be successfully massed or grouped. Not only does this look good, but plantings of this type are low maintenance, requiring very little to no pruning. Although many of the dwarf conifers are very easy to use in the landscape because they have predictable forms, subtle textures, and useable colors, some can be quite grotesque, that is, out of the norm as to what most people would prefer for their landscapes. Yes, there are those of us that admire and love plants of this nature, but when used inappropriately in the landscape, they can look out of place and therefore should be used sparingly. These forms and others such as those that are brightly colored or those with rigid or thin vertical forms are highly focal and command attention, care should taken when placing them into any planting because they can very easily disrupt the focus and balance of the overall landscape. One should use restraint and judicious placement when using these unusual forms. | ||||||||||||||||||||||||||||||||
|
This garden resource is for you. We welcome your comments and suggestions.
Email us on our Feedback Form
.
|
