Growing Conifers: the complete illustrated gardening and landscaping guide

John Albers has highlighted his garden of 20 years in Bremerton and his passion for sustainable gardening practices in two previous books. Now, he turns his attention to a favorite plant group: conifers, especially dwarf and small cultivars. He is very clear in his reasons for writing the book. “Given the horticultural and ecological importance of urban conifers, it is vital that all of us do our part to restore conifers to our urban environment.”

More than just a gardening book, “Growing Conifers” is a good introduction to the botany of conifers. The narrative description of each genus and species gives clues to help with identification, as do the excellent photographs by David Perry. It also explains the origins of the beloved dwarf forms, including many found in the Pacific Northwest, either as mutations in the wild or in nurseries.

The author walks the reader through the process of assessing a garden and developing a design, with the liberal use of suitable conifers. But he doesn’t stop there. He also gives careful instructions for planting and sustainable care of these long-lived plants, and even the basics of propagation.

The design elements also include good companion plants. An example being clematis, especially if they are species that come from lean soil, as Albers believes neighboring plants should share the water needs. However, “sometimes rules can be broken for the sake of a greater good […] for the sake of creating a beautiful garden vignette that warms the heart and soothes the soul.”

Excerpted from the Fall 2021 issue of the Arboretum Bulletin

On wind-sail pruning

There’s a self-described tree service knocking on doors in my street, trying to get people to pay them to do “wind sail reduction” on their trees. My neighbor just agreed to have them prune 17 of her conifers. Bad idea, right? Can you point me toward resources so I can dissuade her from going ahead with this plan?

Yes. The Washington Department of Natural Resources published an article, “Trees Don’t Wind Sail, Do They?,” in their online newsletter, Ear to the Ground, 12/20/2011. Here is an excerpt:
“Some people claiming to be tree experts will tell you that ‘wind sailing’ is a great way to protect your trees from wind damage. You may have heard this fabricated notion of thinning limbs from trees in order to make them stable during wind storms. This improper pruning technique is promoted to supposedly make trees safer in the wind by allowing wind to pass through the canopy of a tree, thus reducing movement and strain on a tree. Not so!

“This may sound reasonable and may even seem to have some logic behind it. But beware–the truth is, there is no scientific study that shows thinning is wise or safe way to decrease resistance during a wind storm.

“Actually, many studies have shown that the outside limbs can divert some wind from the center of the tree and act as a buffering shield. Aggressive thinning, on the other hand, can make the remaining branches more vulnerable to failure; left isolated, these limbs must take on the elements alone. Pruning out a major portion of a tree’s canopy for the sake of staying upright during a wind storm harms most trees in the long run.”

The DNR has another, similar article from 12/6/2012 in their Tree Link News entitled ‘Windsail Reduction:’ A Northwest Controversy.’

You can also suggest that your neighbor speak to someone at Plant Amnesty, a local organization dedicated to teaching the community about proper pruning techniques (as well as informing them about ill-advised methods!).

Conifers, Effect of storms, Pruning

on monoecious plants and bisexual flowers

My neighbor says his Deodar cedar tree is bisexual, and it’s the male cones that are making so much pollen this October. He seemed to be saying this was unusual, and that not all cedar trees were like this, with both male and female cones. What’s the story?

Cedrus deodara is monoecious, which means that an individual tree will bear separate and unisexual male and female flowers. If the tree had bisexual flowers, each flower would be ‘complete’ and ‘perfect,’ that is, with male stamens and female pistil in each flower. So it’s clearer to call the tree monoecious than to say it is bisexual. According to Wayne’s Word: An Online Textbook of Natural History, “about 90 percent of all flowering plants have bisexual flowers with both male (stamen) and female (pistil) sex organs. The remaining 10 percent have unisexual male and female flowers on the same plant (monoecious species) or male and female flowers on separate plants (dioecious species).”

Most conifers (like true cedar) are monoecious. The male pollen cones are 2 to 3 inches long by October, and are found in great number on the lower parts of the tree. Female flowers are tiny, and usually found high up in the tree. Female seed cones take two years to mature. You might wonder how pollination can take place if the female flowers are up high and the pollen is down low. Conifer pollen is wind-dispersed, so it might seem arduous for it to reach the female flowers up above. However, if you consider the geographic origins of the true cedars, you will notice that Deodar cedar is also called Himalayan cedar and like the cedar of Lebanon (C. libani) and the Atlas cedar (C. atlantica), its native range is mountainous. Imagine cedars growing on a sloping mountainside, and you can easily picture the pollen drifting downward to female flowers on the trees below.

planting for slope stabilization

I live in a condo. The conifers on the site are beginning to obstruct the view of the neighbors. Our covenant with these neighbors says trees must not exceed a height of 25 feet. Last year several of the conifers were topped and others removed. Our concern now is that we may have to either top or remove more trees. We don’t want to block the neighbors’ view but we also don’t want to destabilize the ground – we all live on a hillside. What can we do over the next 5, 10, 15, 20 years to decrease the number of conifers and replace them with other trees that will be neighbor-friendly and keep our hill stable?

The short answer is to plant shrubs and groundcovers.

The long answer is that slope stabilization is a serious concern and deserves expert advice. Get started in your research by reading the articles produced by the Washington Department of Ecology:

Slope Stabilization and Control Using Vegetation.

Your condo association may want to hire a consulting arborist and/or a civil engineer (“To locate technical experts such as experienced registered engineers specializing in geotechnical and/or drainage projects, use local telephone directories or call the Seattle or Kitsap branch of the American Society of Civil Engineers (ASCE) for membership references.” from DOE site)

For an arborist referral try:

Plant Amnesty

The Pacific Northwest chapter of the International Society of Arboriculture has information about hiring an arborist.

The International Society of Arboriculture can also help to narrow the search to your area.

pruning Thujopsis

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.

best time to plant conifers

The nursery recommended waiting to plant a Cedrus deodara until after the first hard frost. As we are in USDA Zone 7 (the lower limit for a deodar), I’d think we would want to get it in the ground as early as possible. Any idea what the rationale is behind this advice?

I am really not sure what their rationale might be. I agree with you that planting in the fall is preferable. Here is information which supports this:

Excerpt from Brooklyn Botanic Garden booklet on conifers:

“Across most of the country, spring (early or late, depending on how far north you are) and early fall, when temperatures are cooler and rainfall more abundant, are the best times to plant conifers. To reduce transpiration or water loss from the tree, plant on an overcast day when there is ample soil moisture.”

I don’t know if your tree was a bare-root specimen or container-grown. Here is what Keith Rushforth says in his book Conifers (Christopher Helm, 1987):

“Bare-rooted stock can only be planted during the dormant season. This restricts planting to the period November to April. Planting during midwinter is better avoided, because cold, dry winds during the winter can desiccate the young plants before the roots have been able to make new growth. Planting after April is only feasible if the plants have been held dormant in a cold store.

Container-grown stock can be planted out during most of the year, although the period of maximum growth from late May to early August is better avoided unless watering is no problem. A check should be kept on whether winter-planted stock needs watering; it is very easy for the compost to dry out during dry periods in the winter.”

Based on the above, it seems like a good idea to plant now (fall).

best procedures for preparing planting holes

I am going to take my 6-foot tall Wilma Goldcrest out of the giant pot it is currently in, and plant it in the ground. I am seeking some sort of consensus on how to prepare the hole into which the tree is going. Someone said that I should not put compost in the hole because that will encourage the roots to just stay in the area of the hole. If that’s the case, then shouldn’t the “no compost” rule apply to all new plantings (which, of course, it does not)? Also, when should I fertilize the tree and what kind of fertilizer should I use? I always use organic fertilizers. What about putting some bone meal in the planting hole to feed new root growth?

I refer you to the following information from Washington State University Extension horticulturist, Professor Linda Chalker-Scott, who discusses planting procedures in her book, The Informed Gardener (University of Washington Press, 2008). She says that the planting hole need only be the depth of the root system, but should be twice the width. She advises against amending the planting hole in any way: Backfill the hole with native soil, not a soil amendment. The idea is not to ‘spoil’ the plant by putting rich compost just in the hole, which will deter the roots from spreading out into the surrounding area.

Her debunked gardening myths may also be found online. This one addresses soil amendments and planting. She also addresses the use of bone meal as a planting amendment.

‘Wilma Goldcrest’ is a cultivar of Cupressus macrocarpa, or Monterey cypress.
The University of California’s Garden Information publication on “Pines and Other Conifers”(including Monterey cypress)says:
“Pines and conifers require less fertilizer than most other trees and shrubs. Heavy fertilizing can promote rank, unsightly growth, destroying their natural, symmetrical, picturesque form.” If you do wish to use fertilizer, a dilution of something like seaweed or fish fertilizer would probably not be harmful.

Here is more about fertilizing conifers from University of Minnesota Extension Horticulture.

Excerpt:
“Why Fertilize?
The plant itself will often indicate when it needs fertilizer. If growth rate and needle color are normal for a particular variety, fertilization is not necessary. If new growth is sparse or slow, or the needles are not a healthy color, or are shorter than normal, you should probably fertilize. Keep in mind, however, it is not unusual or abnormal for newly transplanted evergreens to exhibit slow growth until they’re re-established.
Regular fertilization may be recommended if you are trying to grow evergreens in a less than ideal site, such as very sandy or heavy clay soil, or if the plant has suffered damage from insects or disease. You might also wish to fertilize to encourage more rapid growth in relatively young evergreens.”

Local garden writer Ann Lovejoy says the following in her book, The Handbook of Northwest Gardening (Sasquatch Books, 2007): “I rarely feed plants directly, preferring to feed the soil with what are called ‘feeding mulches,’ made of materials such as compost, seed meals, kelp, and fish meals.”

on topping trees

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.

on selecting trees

We would like to plant a special evergreen tree that would be a large heirloom or heritage tree. We would like this to be the centerpiece of our back yard. We know the type of trees that typically fall into this category will be slow-growing, so we want to plant it soon so that it will be big enough for our grandchildren to climb in, swing from, play under, etc.

We would like a tree that is quite large and wide (possibly even wider than it is tall, around 40 feet tall x 40+ feet wide), with branches that start relatively low on the trunk, but do not go all the way to the ground (so you could both climb into it and have a picnic table under it).

I recommend visiting your local arboretum. If you are in the Seattle area, the Washington Park Arboretum is one place where you will find many examples of mature trees, some of which are coniferous evergreens, some of which are broadleaf evergreens. There are also many useful books to help you select the tree that best suits your needs. Since you are interested in evergreens, I particularly recommend Richard Bitner’s Conifers for Gardens: An Illustrated Encyclopedia (Timber Press, 2007) and Portland, Oregon author Sean Hogan’s Trees for All Seasons: Broadleaved Evergreens for Temperate Climates (Timber Press, 2008).

Here are websites that are useful in narrowing down tree lists once you have a few ideas in mind. (Note: Some of the sites have a zone option, i.e. where the trees grow best. Seattle is in USDA Zone 8b & Sunset Zone 5). In some cases, you can narrow down the selection even further, by selecting tree attributes (see the SelecTree site below).

Virginia Tech’s Department of Forest Biology and Environmental Conservation has a series of
Tree Identification Fact Sheets. This site is best for descriptions when you already have a species in mind.

Search the SelecTree database from CalPoly.
The best way to get a good list (with numerous options) is to click on Select Tree by Attribute.

A classic source is the USDA Forest Service internet version of Silvics of North America. It will not help with selection since you will need to know what species you want, but it will provide more information than you will ever need.

shrubs and trees to view from below

Are there any lists of shrubs/small trees that are best viewed from below, such as Styrax or Halesia?

While there are no lists of shrubs/small trees best viewed from below, there is a list of trees with weeping habits in The Pacific Northwest Gardener’s Book of Lists (Ray and Jan McNeilan, 1997). Many genera of conifers – Cedrus (cedar), Chamaecyparis (cypress), Larix (larch), Picea (spruce), Pinus (pine), and Tsuga (hemlock) – have weeping forms, often indicated by a variety name ‘Pendula’ or ‘Pendulum’. There are weeping birches (Betula), beeches (Fagus), and cherries (Prunus), too.

You are correct about Styrax and Halesia. Additionally, I ran across a few individual species that may be of interest to you as I researched this question:
–Davidia involucrata
–Laburnum anagyroides
–flowering currants, Ribes spp.
–flowering cherry trees, particularly Prunus padus
–various plants in the Ericaceae family have bell-shaped flowers that hang on the underside of the stem.

I would add that any tree which has a naturally graceful branching pattern and/or delicately shaped foliage (such as Japanese maples) would be pleasant to view from below, as well as from other angles.