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Guide to Growing Eucalyptus
The family Myrtaceae contains the genera Angophora, Corymbia, & Eucalyptus.
The latest published documents has listed 789 known species in 1996, with an additional 123 subspecies or varieties. Further species are still to be named with a known current total of 912.
There is a move to further divide the Eucalyptus into seven different genera: Blakella, Corymbia, Eudesmia, Gaubaea, Idiogenes, Monocalyptus and Symphyomyrtus.
Only 5 species occur exclusively outside Australia, they are Eucalyptus deglupta, E. urophylla,E. orophila, E. wetarensis and Corymbia papuana.
The differences between Angophora - Corymbia - Eucalyptus:
Angophora: Currently contains 12 species, all are native to Eastern Australia, they do not have an operculum (bud cap), the flowers are always white and the leaves are always opposite.
Corymbia: Contains 113 species, made up of bloodwoods and ghost gums.
Eucalyptus: All others. Flowers are predominantly white or cream in color, however, other colors are pink, yellow, red, purple or orange. Adult leaves are usually different than juvenile leaves and are mildly to densely aromatic.
EXPECT THINGS TO CHANGE !
Propagation: We propagate all of our Eucalyptus by seed. Limited research on cuttings, root division, etc. has been done throughout the world, the main focus is still on seed germination. Some seed must experience a cold dormancy period before germination will take place, this is commonly known as "stratification." Other seeds may be planted as soon as the seed is obtained. New techniques are being tested using "Smoke Water" with good results. "Smoke Water" is basically obtained by piping smoke from burning native vegetation through water. Chemicals found in the "smoke" are released/dissolved in the water. The Smoke Water is then poured over the seed and media. We have also improved our germination rates with some species using other seed enhancing substances like Potassium nitrate or Gibberellic acid, but the average person can just plant the seeds and still generally have good germination.
Providence: The best Eucalyptus seed to work with for cold hardy species comes from high elevations in cold areas.It goes to reason the cold hardy seeds come from the coldest places and tropical varieties from warm places. Tropical plants do not over-winter outdoors in our Virginia climate, but our cold hardy plants can do fairly well in tropical zones.
Types of Eucalyptus: Broken down into seven categories:
1. Mallee: Low growing types with a number of stems rising from what is known as a lignotuber. This is a modified root system and enables the plant to produce new shoots even after it has been destroyed above ground (generally by fire or cold). If a cold winter knocks back your Eucalyptus, it can usually be cut back to the lignotuber and the plant will re-sprout and grow again. Eucalyptus Cinerea, although only rated hardy to about 14 degrees, has survived actual temperatures of minus –20 degrees at our Louisa Virginia nursery. The plant was cut back to the ground in early spring and still had 14 feet of new growth within two years. Not all Eucalyptus have lignotubers.
2. Gums: Shed a layer of bark from most or all of the trunk and branches. It leaves a smooth, usually light colored trunk. Some examples are Eucalyptus Aggregata, E. Archeri, E. Bridgesiana, E. Cinerea, E. Neglecta.
3. Stringybarks: The bark is made up of long, string-like fibers. The bark is also usually gray to reddish brown. The tree trunks are normally long and straight and make good timber. Example: Eucalyptus youmanii.
4. Peppermints: These species have a fine, interlaced bark. The bark may be fibrous, but the fibers are very fine and crumble when rubbed. The leaves have the characteristic peppermint odor when crushed. Examples are Eucalyptus coccifera, E. dives, E. nitida, E. pulchella, E. radiata, E. tenuiramis.
5. Boxes: Have flaky, scale-like bark over the trunk and all branches. The leaves and buds tend to be smaller than on other Eucalypts, the wood is generally close grained, durable and excellent timber quality. Examples are Eucalyptus lansdowneana and E. polyanthemos.
6. Ironbarks: Have a hard, deeply ridged bark. Examples in this group include Eucalyptus leucoxylon, E. melliodora and E. sideroxylon.
7. Yates: Are usually smaller in habit with very large gumnuts. The flowers are produced in what is known as a gumnut, the seed is carried inside this nut and takes about 2 years to mature. E. lehmannii has very large gumnuts.
Hybrids: Many of the Eucalypt species will cross-pollinate and form new species. We often see new species in the daylily family as an example.The Eucalyptus seed we receive from Australia usually breeds true, yet, there are times when there are distinct differences in plants from the same seed lot.
Fertilizing: One word sums it up - DON'T! When it comes to fertilizers, one key thing to remember is that most all Australia plants do not like phosphorus. In fact, phosphorus toxicity is a real challenge in growing some Australia plants. Phosphorus is the middle number of the N-P-K ratings found on fertilizers. We have found that most of the Australia plants we grow receive sufficient phosphorus from the soil and no additional fertilizers are needed. I am going to make a distinction here, we grow in a "soilless" media that contains no earth or dirt. Our nursery media is primarily bark, peat, perlite and vermiculite. As such, it contains no nutrients. Generally we add fertilizer into our growing media for balanced plant growth. When you plant out your specimen into the landscape, you do not need to add any fertilizers.
Most Eucalyptus species do well in average drained soil, although some species will tolerate more moisture such as Eucalyptus aggregata E. rodwayi, E. camphora, E. crenulata, or E. gunnii species. These occur naturally on un-drained sites that are frequently waterlogged. Australia soils, for the most part, are very shallow and well drained being either a sandy soil over sandstone or granite. A well drained soil would be much preferred over clay.
Planting your Eucalyptus:
Prepare the planting area:
Providing Winter Protection:
Of course, not everyone will need to go to these extremes for winter protection, just us folks trying to grow Eucalyptus species in very cold climates.
Picture 1 below shows several different ways to provide protection: Plastic bags, (we also tested short sections of large diameter pvc pipe we had on hand.)
Plastic bag/pipe test Winter protection using plastic bag
WHY GROW EUCALYPTUS ?
Aromatherapy is quite popular these days. Although it may be cheaper to buy a bottle of Eucalyptus oil, the pleasure of "home grown" can be much more rewarding.
Preserving Eucalyptus: If you want to preserve fresh foliage, use a 50-50 glycerin and water mix. Stick the cut ends of stems in this mixture in a low light area, in about 2-3 weeks, the Eucalyptus will have absorbed the glycerin and be ready for use. Glycerin can usually be obtained from a pharmacy and you can easily do your own preserving. Much of the Eucalyptus I have seen in the craft stores all smells alike and has been obviously dyed in different colors. To each his own, but why waste the beauty of the many varied "natural" scents of Eucalyptus? You certainly won't find any naturally lemon scented Eucalyptus at your craft store! Talk about fragrance, the lemon scented Corymbia citriodora has got to be tops!
Red to Pink Flowering Types:
Purple: Only one species, E. lansdowneana var albopurpurea
Yellow: E. campaspe, E. dolichorhyncha, E. erythrocorys, E. leucoxylon, E. orbifolia, E. pachyphylla, E. pimpiniana, E. presissiana, E. stoatei, E. woodwardii, E. youngiana.
Sugar Gliders: We ARE NOT Sugar Glider breeders, nor do I consider myself as a professional when it comes to their habits or nutritional needs. Please do not ask me to tell you what to feed your sugar glider! I am not experienced in the nutritional needs for sugar gliders. You can view this link gliders to see what "others" say about sugar gliders.
Parakeets, budgies, parrots, snakes, stick insects, lions, tigers and bears oh my!..... Don't even ask!
Size and growth rates:
Sizes in Eucalyptus range from about 3’ for the E. Kruseana or Brookleaf Mallee to others that are well over 200 feet tall. Actually, the tallest hardwood tree in the world is a Eucalyptus species, Eucalyptus regnans. Documented records indicate this tree grew to a height of 480’ before the wind broke it off ! It is even taller than our giant sequoias out in the western part of the USA.
Cold Tolerant Species:
USDA Climate Zones: These links provide information to help you determine your local climate zone: http://www.usna.usda.gov/Hardzone/ushzmap.html
Eucalyptus as house plants:
Use a large pot and place it in a south facing window area with bright light with moderate water over the winter.
Some of the most popular species for house plants: Corymbia citriodora, ficifolia, Eucalyptus Baby Blue, bridgesiana, cinerea, glaucescens, gunnii, nicholii, parvula, urnigera. (Occasional pruning is needed)
Eucalyptus growing in tubs or containers:
To restore a leggy or leaning tree: Cut the tree back to 4 to 5 inches above ground. Make a smooth, slightly sloping cut to the south to facilitate water run-off. The coppice shoots develop from the dormant buds in the live bark or from the lignotuber buds. Many shoots develop, but they gradually thin themselves out. Finally two or three remain, select the best one to develop as your tree.
Pollarding: Can be done to trees from 3 to 6 years old. This is commonly done on the faster growing Eucalypts to lower crown height and encourage branching at the top of the tree. The faster growing species will tend to make a single trunk, shed their lower branches and the crown advances up the tree. Cut off the main trunk between 6 and 10 feet above ground. Do not remove any of the side branches. The crown will develop rapidly and one branch will gain dominance and will be your new main central leader.
Specimen tree: If you want a specimen tree with a single trunk for the first 6 feet, do not prune away any of the lower branches until the tree has had two seasons growth. You can remove any lower branches after that. No pruning is necessary for the faster growing species because they will shed their lower branches naturally.
Hedging: Species suitable for hedging include Eucalyptus archeri, coccifera, parvifolia and subcrenulata. It is essential to prune the plants at the end of the second seasons growth to begin to shape them for a hedge. Remove 1/3 of the height and cut to an inverted "V" or pyramid shape around June. By hedging at this time, the naked buds are able to develop before the end of the growing season so that new growth starts immediately in spring.
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Last modified: 08/28/11