I recently purchased two Eucalyptus gunnii trees and one E. dalrympleana, which are still in their pots. I have them in full sun, facing south. I have been watering them every day – is this appropriate? I know that the gunnii tolerates waterlogged soil.
All Eucalyptus prefer full sun and well-drained soil. They are very drought tolerant when established.
Source: Manual of Woody Landscape Plants, by M. Dirr, 1998, p. 352.
If your plants are in terracotta containers they will need daily water. If they are in non-porous containers you have a bit more leeway, but do not let them dry out while they are young.
Another consideration is whether you plan to grow these trees in containers permanently, or if you are going to be moving them into the garden. If you plan to keep them in pots, bear in mind that these trees will get quite large (70 feet tall by 20 or more feet wide), so you may end up needing to do a lot of pruning from the top as well as root pruning. Sometimes, even when planted out into the garden, urban gardeners with small lots will coppice a tree like Eucalyptus gunnii or E. dalrympleana annually so that it does not overgrow its site, and so that the rounded, juvenile leaves are maintained. See the Royal Horticultural Society’s page on eucalyptus pruning for additional details.
If your plan is to move the trees into the garden, it is best to do it when they are relatively young and small, as Eucalyptus generally dislikes root disturbance.
I’m looking for resources on proper pruning or rejuvenation for Thujopsis. We have a 50-60 year old specimen.
According to Michael Dirr (in Dirr’s Hardy Trees and Shrubs: an Illustrated Encyclopedia), Thujopsis dolabrata is “too beautiful to mutilate with pruning shears.” This website of a Seattle-area gardener suggests that you may be able to prune it lightly by candling the leader.
According to George Brown’s The Pruning of Trees, Shrubs and Conifers (Timber Press, 2004), specimens of this tree vary widely in habit. Some form a definite leader, while others are “untidy, spreading shrubs. Of those which grow out of this shrubby habit, a number produce rival leaders and the result is a small tree made up of slender upright trunks with their supporting branches.” If your tree has multiple leaders, it is probably too late to prune them–this kind of pruning would be done on a younger tree.
I spoke with a docent at Seattle’s Japanese Garden, which has Thujopsis, and she said that they are not pruned, except to remove dead, damaged, or diseased branches. You may find this general information on pruning conifers from Brooklyn Botanic Garden useful.
Excerpt:
“As with any plant, dead or diseased conifer branches should be removed immediately, regardless of the time of year. Any other pruning should be done when the plant is dormant. Unlike many deciduous shrubs, most conifers can’t re-sprout from older wood (yew, arborvitae and podocarpus are exceptions), and so a good rule of thumb is never to remove more than one-third of the total growth at a time. If you prune too drastically, the plant may never fully recover. Many of the dwarf varieties never need to be pruned, but do appreciate some thinning to allow air and sunlight to penetrate to the interior of the plant.
The most common method of pruning evergreens is known as ‘cutting’ or ‘heading’ back. Only part of the branch is pruned; the terminal or tip growth is trimmed to side or lateral buds or branches. This promotes thicker, more compact foliage and a smaller overall plant.”
It sounds as if you should do the bare minimum in terms of pruning. If you really need to reduce the tree’s size, it would be wise to consult a certified arborist.
An issue has come up within our local homeowners association regarding some of the evergreen trees in our common areas. The issue is that about 20 or so trees have “deformed tops” – the tree has grown straight, but in the course of nature, the top has either broken off in a storm, or the tree has grown irregularly, developing a “hook” or “lever” at the top of the tree. This has lead to considerable discussion and (unfortunately) argument within our association. A tree service was hired by our association and they recommended “topping” the evergreens with the “lever” on the top. They stated these “levers” become “sails” in the wind and weaken the trees. One side believes these trees are hazardous and should be topped for safety, the other side believes they should be left as they are.
Searching through resources on the internet has led me to believe that topping these trees is the worst thing that could be done for the future health of the trees, not to mention the effect on property values due to the unsightliness “topping” causes.
I am interested in obtaining any information on the subject and would be open to discussing this with an arborist if possible, preferably someone who is very familiar with northwest evergreens.
You are right to be concerned about topping. The discussion probably should be whether to remove the trees if they pose a true hazard, or leave the trees if they do not pose a hazard. A damaged leader can be remedied, but do not take my word for it! You need a CERTIFIED arborist. If the arborist is hired as a consultant he will not have any incentive to recommend work that is unnecessary (this is why I am suspicious of the tree-service company).
Here are two organizations to contact for referrals:
Plant Amnesty: Plant Amnesty
(See also Plant Amnesty’s page about topping trees.)
PNW Chapter of the International Society of Arboriculture (the organization that grants certification) International Society of Arboriculture or Trees Are Good, the website of the International Society of Arboriculture.
You want someone who has experience with tree hazard evaluation.
Another source is Arboriculture by Harris, Clark and Matheny that discusses what to do when a conifer loses its leader.
Is it possible to arborize a large Euonymus shrub (by
selectively pruning many of its branches to create a tree shape), as one
can with rhododendrons? I prefer pruning over removal, if that option is
available to me. What tips can you offer for pruning Euonymus in this
way?
It is a little difficult to offer advice without knowing which species of
Euonymus you are growing. There are many, some evergreen and some
deciduous. The pruning method varies according to the species. See the
link here, from Oregon State University, for information on some of the
different species.
If you would like to get back to me with information about the species, I
will be better able to assist you. For now, here is general
pruning information and links which may be of use.
Seattle gardening expert Cass Turnbull and the organization Plant Amnesty
offer helpful pruning hints. Excerpt:
Punch List for Tree-Likes. Take out:
- Dead wood
- Suckers from trunk, roots, or branches
- Crossing/rubbing branches (the worst ones)
- Branches hanging on the ground
- Wrong-way branches
- Too-far-up/too-far-down branches
- Parallel branches
- Head back to shorten (if necessary) on shrubs, not trees.
- Tree-likes vary in the degree to which they may be thinned before they
sucker back or suffer dieback. Removal ranges from approximately
one-eighth to one-third total leaf area.
Another excerpt, on arborizing shrubs:
Other people strip up all the lower limbs of shrubs they consider too
big, making them somewhat reminiscent of lollipops or ostriches. I
hesitate to mention stripping because of these common abuses. However,
there are some instances where removing the lower limbs of a shrub is a
good option. It will depend on the type of plant and its location. Don’t
strip up plants just because they seem too big. Good candidates are ones
that are actually impeding foot traffic or totally obscuring windows. The
best subjects are non-suckering tree-like shrubs. Usually they are
broad-leafed evergreens, such as rhododendrons, pieris, camellias, or
strawberry trees (Arbutus unedo). Stripping up works best on very old
shrubs. By cutting off the lower branches you are “arborizing” them.
“Arbor” means tree, and you are turning your big shrub into a small tree.
English laurel is a good subject. Instead of a giant oppressive blob, you
can have an open, sort of oriental-looking, small tree. In fact, one
could say that most of these plants are trees in their native habitats.
They start out as shrubs and grow into understory trees in their
adulthood. We just expect them to stay in the shrub-like juvenile stage
forever.
Some shrubs can be arborized, meaning that they can be pruned into small
trees.
Pause before you strip, though. It’s a major step. Look inside your shrub
and evaluate how the trunk will look when it’s exposed. Is it fat? Good!
Does it lean and curve gracefully? Great! If possible, endeavor to leave
some branches lower down and inside to avoid the stripped or gutted
appearance. To alleviate the lollipop effect, thin out the upper canopy
of leaves, too. It should look a bit lacy and like a tree, not like a
solid ball. Don’t arborize more than a few plants in your landscape, it
begins to look silly if you do too many.
Be sure to leave enough leaves to collect sunshine in order to feed the
plant. Shrubs and trees vary from species to species in the degree to
which they will let you put them on a diet. Trees and shrubs which have
been starved by over thinning usually succumb to death in a drought or
freeze. Be sure to help heavily thinned, non-suckering plants by
supplying sufficient water and fertilizer.
Could you provide me with information on pruning Red Gravenstein?
I have a small hornbeam tree, Carpinus japonica, roughly 6 feet tall. It has never been pruned and was just transplanted to a small shade garden, close to a path. It will need to be pruned to keep the canopy high. Should this tree be pruned lightly? Is it at a good age or time to prune and to make a single trunk tree? Would fall be the best time to prune?
According to the American Horticultural Society’s Pruning & Training (edited by Christopher Brickell, DK Publishing 2011), Carpinus species tolerate pruning well, but it is best to do it from late summer to midwinter, to avoid severe bleeding of sap. Your tree is quite small, and it should be fine to do light pruning and remove any branches that are going to interfere with the path. (Heavy pruning can result in twiggy growth.) It’s not uncommon to prune it to a central leader standard (more upright form).
I have a Magnolia tree that is planted next to our house. This year, there were not very many blooms and the tree is getting rather bushy-looking. When is the best time to prune it and how much can be pruned?
According to the American Horticultural Society’s book, Pruning and Training by Christopher Brickell (DK Publishing, 1996), mature Magnolias should not be pruned unless it is essential. Many species will bleed from pruning wounds, and should only be pruned from summer to before midwinter. Summer-blooming Magnolias can be carefully pruned to reduce size by removing selected branches. The book Pruning: A Practical Guide by Peter McHoy (Abbeville Press, 1993) recommends doing this in late fall or early winter.
Below is a link to an interesting discussion on the how and why of pruning a Magnolia, from University of British Columbia Botanical Garden’s online forum.
I have two questions. When is a good time to prune Parrotia persica?
What can I do about a canker on the trunk of a Southern Magnolia?
According to the American Horticultural Society’s Pruning and Training (edited by Christopher Brickell; DK Publishing, 1996), Parrotia persica should not need a great deal of pruning, but if you do prune, it should be from fall to early spring.
If you are growing it as a shrub-like shape, you should not thin or shorten laterals, as this will cause congested growth. If you are growing it in a tree-like form, the trunk can be cleared to about 5 feet, allowing the crown to branch. If needed, you can shorten pendulous tips to give clearance for walking beneath the tree. Once established, this tree should not be pruned. If the tree was a grafted specimen, remove any suckers.
This information from University of Florida discusses Southern magnolia (Magnolia grandiflora), and says that cankers may kill branches, but the affected branches may be pruned.
Excerpt:
“Canker diseases will kill branches. Cankers on branches can be pruned out. Keep trees healthy with regular fertilization and by watering in dry weather.”
Magnolias by Rosemary Barrett (Firefly Books, 2002) says that
“various cankers, such as nectria canker, dieback and trunk decay can all be dealt with by cutting out the dead or diseased wood. Rarely will any of these diseases cause the death of the plant.”
I have a big pin oak that needs to be pruned. Maybe 1/3 of the leaves have dropped. Is this a good time to prune or should I wait a week or two?
The American Horticultural Society’s Pruning & Training (DK Publishing,
1996) says to prune pin oak (Quercus palustris) as you would white oak,
that is, when the tree is dormant, in winter or early spring. Pin oak
can be trained as a central-leader standard, but if this is a mature tree
which was not trained this way, do not attempt it now. Established trees
should not need much pruning at all, so only prune what is dead,
diseased, or damaged, or any branches which are drooping, in order to
provide clearance.
The Sunset Pruning Handbook (1983) says the following:
“Pin oak is a pyramidal tree when it’s young. It forms a rounded top as
it matures. during the pyramidal stage, its lower branches are
down-sweeping. If you remove the lowest branches to gain walking space
beneath the tree, the limbs above will bend into a down-sweeping
position. When the tree is mature, the down-sweeping process will stop.
You can then cut off lower limbs to create a tree suitable for walking
under.”
What is the definition of topping a tree?
The Morton Arboretum Tree-Care Handbook calls topping “indiscriminately sawing off large branches.” (1994)
According to the Washington State Department of Ecology’s Vegetation Management: A Guide for Puget Sound Bluff Property Owners (May 1993, p.23), the practice of topping usually refers to cutting the upper portion of the main leader (trunk) in conifers and to the removal of all branches at a particular height in deciduous trees. Topping is not advised.
Plant Amnesty has loads of information about topping – including why it should not be done – at the following link: 5 Reasons Not to Top.