Spring Pollen

Posted on April 19, 2014 by admin
The Gymnosperms were spreading their pollen last week. Like nearly all plants, they fertilize their seeds by pollen moving from the male parts of the flower to the female. In the case of Conifers (a gymnosperm) they have separate male and female “flowers” known as cones.  
Here are some male Hemlock cones. The white specks are individual pollen grains.

Several male Hemlock cones. The white specks are individual pollen grains.

Here you can see immature female Hemlock (Tsuga heterophylla) cones.

Here you can see immature female Hemlock (Tsuga heterophylla) cones.

  Conifers aren’t as evolved as “true” flowering plants (the angiosperms), so they rely on the wind as opposed to a pollinating insect like a honey bee, to get the pollen to the right place. This works just fine, but it means they have to produce copious amounts of pollen to ensure it reaches and fertilizes the female cone. Great for the trees, not so much for the people with allergies.  
Male (the smaller ones pointing down) and immature female cones. The male cones will fall off shortly. The female become the typical Douglas fir cones, maturing next spring and falling off the tree after that.

Male (the smaller ones pointing down) and immature female cones. The male cones will fall off shortly. The female become the typical Douglas fir (Pseudotsuga menziesii) cones, maturing next spring and falling off the tree after that.

There was so much pollen coming off the Douglas firs during a warm day last week, that my climbing helmet starting to have a golden sheen.

There was so much pollen coming off the Douglas firs during a warm day last week, that my climbing helmet starting to have a golden sheen.

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Fruit Tree Pruning

Posted on April 4, 2014 by admin
There are two basic times of the year that it’s best to prune fruit trees; dormant and summer. Most people prune when the tree is dormant (no leaves) because it’s easier to see what and where you are cutting. But people often forget that dormant pruning has a stimulating effect on the tree’s growth. That means you are encouraging new growth the next growing season- most noticeably directly below where the cuts are made. This is very useful and desirable in many cases, but not all. Sometimes you may want to slow the growth of a tree. “I want to keep it small” I often hear people say- this is when summer pruning is called for.
Summer pruning has a dwarfing effect meaning you can control the shape and size of your tree (and thus where the fruit grows) without it sending up so many vertical fast growing shoots known as water-sprouts, the next year. Summer pruning tends to dampen water-sprout growth. The growing season is also a good time to prune especially vigorous young trees, or extremely overgrown older trees that may be getting too big for their space or producing fruit out of reach. Pruning in the summer can begin to stop the endless cycle of pruning out hundreds of water-sprouts and suckers every winter.
Before being pruned

Before being pruned

After pruning

After pruning

Often trees that are very overgrown need several years of pruning to gradually come back down to size or be thinned out appropriately. Excessive pruning at any time of the year can result in an abundance of water-sprouts the next year or unduly stress the tree.

A very overgrown tree in which the Quince rootstock has nearly overtaken the pear that was grafted to it.

A very overgrown tree in which the Quince rootstock has nearly overtaken the pear that was grafted to it.

Quite a few branches have been pruned out. More will need to be removed in successive years. One of the pear grafts can be seen growing nearly horizontal on the right.

Quite a few branches have been pruned out. More will need to be removed in successive years. One of the pear grafts can be seen growing nearly horizontal on the right.

      There are still a few weeks left for dormant season pruning. Give me a call or send an email to schedule a free estimate.   Don’t have a fruit tree- Are you interested in planting one? Check out some Washington nurseries for fruit trees and other edible plants. I’m also available to plant trees and consult on their placement in your landscape.
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Goats and Urban Forestry

Posted on January 14, 2014 by admin
As part of the goal to reduce my business’s impact on the environment, this past summer I started a program working with goat owners in the greater Seattle area. When I’m working nearby someone that has goats and I have tree trimmings that goats like (there are only a handful of species they can’t eat), I drop them off for the goats. This reduces the amount of green waste getting trucked around (which equals fewer CO2 emissions) while at the same time providing the goats with some fresh local greenery. All helping to close a few loops in our food system.  

Goats Eating Tree Trimmings from Lee on Vimeo.

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Reaction Wood

Posted on December 4, 2013 by admin
Have you ever wondered how a tree supports itself as it reaches towards an opening in the canopy? Or how a long limb holds itself horizontal? The answer is reaction wood.
A cut limb from a conifer tree showing reaction wood. Notice how the "center" of the branch is actually very near the top of the limb. Compression wood has formed on the underside to keep the limb horizontal.

A cut limb from a conifer tree showing reaction wood. Notice how the “center” of the branch is actually very near the top of the limb. Compression wood has formed on the underside to keep the limb horizontal.

Reaction wood is a special kind of wood that forms on the top or bottom of a limb or leaning trunk. In general conifers “push” and hardwoods “pull”. This means that in gymnosperms (conifers) this specialized wood forms on the underside of the limb or trunk and is called compression wood. In angiosperms (hardwoods) it is formed on the top of limbs and branches and is called tension wood. Reaction wood has different properties than normal growth, being more brittle, denser, prone to cracking, etc. depending on whether it’s a conifer or hardwood.   Source: Trees: Their Natural History. Thomas, Peter
Posted in Curiosities, Tree Care | 2 Comments

Plant Profile: Sea Berry

Posted on November 20, 2013 by admin
Hippophae rhamnoides, Sea Berry or Sea-buckthorn, is a valuable and attractive landscape plant. Besides providing nutritious and tasty berries it also fixes nitrogen into the soil, similar to many members of the pea family (although this is a member of Elaeagnaceae). It’s been used to stabilize soil, as it grows in poor or sandy soils where other plants may not thrive.
Sea Berry or Sea Buckthorn (Hippophae rhamnoides ) berries are known for being very nutritious with high levels of Vitamin C and antioxidants as well as other medicinal properties.

Sea Berry or Sea Buckthorn (Hippophae rhamnoides ) berries are known for being very nutritious with high levels of Vitamin C and antioxidants as well as other medicinal properties.

Being native to parts of Europe and Asia, it’s fairly unusual in Seattle and the Pacific Northwest, but is gaining in popularity and can sometimes be found in local nurseries. I came across this tree in West Seattle a few months ago, it seemed to be thriving and must have been at least 30 years old. Several of the nurseries I list under the Resources section of this website carry many varieties of Sea Buckthorn. Many people find the fruits too tart to eat alone and opt to make a sweetened juice or preserve from them. Besides the high Vitamin content the berries also contain essential fatty acids, unusual for a fruit. When extracted, the oil can be used medicinally and is being studied for treatment of a wide array of internal and external medical conditions.
A very large Sea Berry tree. This one is pushing 20ft, which is unusually tall. It makes an attractive landscape plant that fixes Nitrogen in the soil.

A very large Sea Berry tree. This one is pushing 20ft, which is unusually tall. It makes an attractive landscape plant that fixes Nitrogen in the soil.

  I suggest giving it a try in your landscape if you have a bit of extra room. It’s easy to keep it pruned to size- a recommended harvesting technique is to cut whole branches of fruit, freeze them, and then easily pick or knock the berries off. Transplanting season just started here in the Northwest, so now is a great time to get one in the ground.   Resources: PFAF Raintree One Green World
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Leafhoppers and Spider Mites

Posted on October 16, 2013 by admin
As the summer progresses insect pest damage often becomes more apparent. I was recently called out to a home in the Greenlake area of Seattle to look at a vine maple that was having a pest problem. The tree actually had two different pests feeding on it’s leaves. Leafhoppers and spider mites. Click on the images for a larger view.
A closeup of a maple leafhopper. The small black dots are it's excrement. A sign of a particular type of leaf "juice" sucking insect, species that eat only the outside top layer of the leaf. (magnification ~10x)

A closeup of a maple leafhopper. The small black dots are it’s excrement. A sign of a particular type of leaf “juice” sucking insect, species that eat only the outside top layer of the leaf. Magnification ~10x)

Spider mites (the pale dots in the center of the image) in amongst their webs, on the underside of a vine maple leaf. (magnified about 10x)

Spider mites (the pale dots in the center of the image) in amongst their webs, on the underside of a vine maple leaf. (magnified about 10x, click for larger image.

Leafhoppers feed by sucking the plant juices from the top layer of leaves. This often shows up as a stippling or lighter areas on the upper leaf surface. A couple of low impact ways to control the population are: -Encourage natural enemies such as parasitic wasps. -Hosing the plant with water will work to some extent, but only on the wingless nymphs. Some plants that will encourage parasitic wasps are members of the aster and mint families. One resource I found says that digger wasps, especially mud dauber wasp, feed their larvae leafhoppers as well as many other pest insects. Some of these beneficial wasp species prefer specific flowers, e.g., umbels (a flower shape), sumac, elderberry, milkweed, and Ceanothus species, as the adult wasp’s food is primarily nectar and pollen. In general a variety of wildflowers will help build a diverse population of predator species which can help control the leafhopper population.
A very colorful leafhopper. Magnified about 10x

A very colorful leafhopper. Magnified about 10x

  There are many species of spider mites. Here are a few general control recommendations from WSU. -High levels of nitrogen in the foliage encourage spider mite reproduction. Switch to a slow-release or low-nitrogen fertilizer when practical. -Hose mites from plants with a strong stream of water. -Predatory mites and insects such as ladybird beetles and green lacewings aid in control of mite populations. Avoid use of broad-spectrum insecticides which kill beneficial insects and bees. -Provide proper culture. Healthy plants are more tolerant of damage, while drought-stressed plants are more susceptible. An alternative food source for the predatory mites is grass pollen. So perhaps some ornamental grasses somewhere in your landscape would be a good edition.
Posted in Gardens, Landscapes, Tree Care | 1 Comment

Grafted Forests

Posted on September 24, 2013 by admin
Perhaps while in the forest you’ve seen tree stumps that look something like this.  
Evidence the roots of this former tree are connected/grafted to nearby living trees.

Evidence the roots of this former tree are connected/grafted to nearby living trees.

This was a Douglas Fir (Psudotsuga menziesii) that was cut down some time ago. Instead of the stump dying and rotting away, which would normally happen with this species, it has healed over the “wound”. What made this possible is that the roots of this tree fused or grafted onto roots of the same species growing nearby years ago. This group of Doug Firs is now acting like a single organism, similar to the way a single tree will wound over where a branch has been cut.  
Douglas Fir stump healing over the cut portion.

Douglas Fir stump healing over the cut portion.

There’s another even more amazing network growing through the forests- mushrooms. Their roots (called mycelium) connect to tree roots and other plant roots to form symbiotic relationships where vital nutrients are shared between species- but that’s a whole other blog entry.
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Cherry Brown Rot

Posted on September 17, 2013 by admin
It’s well past cherry season here in Seattle and Western Washington, but earlier this summer you may have noticed a brown mold covering fruits just as they were ripening. This is due to a fungus called cherry brown rot or blossom blight which belongs to the genus Monilinia. Unfortunately it can infect all Prunus species (stone fruits), so there’s still an opportunity to see it out there on fallen plums.  
This entire cherry twig has died, most likely due to the fungus Monilinia laxa. Gumming has occurred where blossoms emerged from the stem. This entire twig (back to healthy tissue) should be removed and destroyed, as the fungus can produce spores on the twig and re-infect the tree next year. The brown mass at the end of this twig are leaves and blossoms that have died from the infection.

This entire cherry twig has died, most likely due to the fungus Monilinia laxa. Gumming has occurred where blossoms emerged from the stem. This entire twig (back to healthy tissue) should be removed and destroyed, as the fungus can produce spores on the twig and re-infect the tree next year. The brown mass at the end of this twig are leaves and blossoms that have died from the infection.

Monilinia laxa and Monilinia fructicola are spread by spores during various (usually wet) times of the year. The fungus infects a number of areas on the host plant. Early in the season it causes blossoms to wilt and die, and sometimes entire branch tips will be killed. The branch ends will then wilt and turn brown but remain on the tree, this is called flagging. Later in the year it can attack ripening fruit, rapidly causing a gray mold to engulf the entire fruit and spread to others that are touching it. It can also cause cankers and twig die-back, sometimes causing the tree to exude sap or gum.   Cherry brown rot can be hard to control, but here are a few suggestions: Avoid overhead watering. Avoid wounding the fruit during harvesting (the wounds are places for infection to occur. Control insects that cause wounds to fruit, (i.e. fruit flies). Prune out infected twigs in late spring or summer- don’t wait until the leaves fall, as it’s much harder to tell what is dead at that point. Remove mummified fruit and dead blossoms from the tree and underneath it, these can lead to re-infection. Space plantings and prune for good air circulation. This allows for quicker drying after rains, and limits moist conditions which are favorable for disease development.   Sources: Washington State University Hortsense Cornell Integrated Pest Management Diseases of Trees and Shrubs 2nd edition. Sinclair and Lyon. page 76. 2005
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Co-dominate Stems

Posted on July 30, 2013 by admin
Co-dominate stems often become a problem in mature trees. Co-dominate stems, or “double trunks”, arise when the terminal growth point on a tree is broken or cut off. The tree then sends up two or more new leaders which compete for dominance throughout the tree’s life.
Multiple trunks/ co-dominate stems emerging from a single trunk. Notice how the bark has become "included" where the trunks press together, creating a weak attachment point.

Multiple trunks/ co-dominate stems emerging from a single trunk. Notice how the bark has become “included” where the trunks press together, creating a weak attachment point.

Problems arise when these multiple trunks grow large in size. They are prone to failure (to varying degrees depending on the species) because as the trunks increase in size there is a smaller percentage of each trunk actually connected to the main stem. They begin to press against one another, trapping bark between the two leaders. It may look like they are attached to each other at this point, but in fact there is only bark between the two trunks.  Windstorms and heavy snowfalls, among other forces, can cause the failure of one or more of the trunks.   I see quite a few trees with multiple tops while working in the Seattle area.  This situation can often be remedied, especially if it’s caught while the tree is young or within 10 years or so of losing its top.          
A classic example of co-dominate stems in a Western Red Cedar

A classic example of co-dominate stems in a Western Red Cedar

A co-dominate stem failure. When a trunk branches into two main stems, the point of attachment is often weak. Notice the area above the "V" shape on the trunk. This is just bark that was pressed against the trunk that is now gone, they were not actually attached to each other in this area.

A co-dominate stem failure. When a trunk branches into two main stems, the point of attachment is often weak. Notice the area above the “V” shape on the trunk. This is just bark that was pressed against the trunk that is now gone, they were not actually attached to each other in this area.

Posted in Tree Care | 2 Comments

Midnight Marauders

Posted on July 15, 2013 by admin
A large number of garden pests are nocturnal. I took these photos in my garden in the Wallingford neighborhood of Seattle around midnight this spring.  
A garden snail and cutworm eating an Iris leaf late one night.

A garden snail and cutworm eating an Iris leaf late one night.

If you’re wondering what is eating your plants try going out with a flashlight at least an hour after dark. You may be surprised by what you find. Those notches on your Rhododendron leaves? That may be from an adult root weevil, which feeds at night. Seedlings in your garden full of holes and covered with slime trails? Probably slugs or snails. With just A few nights of collecting it’s possible to really diminish the population of some pests such as the cutworms pictured- especially in smaller urban gardens. If you’re interested in identifying pests you find, I recommend checking out the book Garden Insects of North America by Whitney Crenshaw.  
A garden snail on a bergenia leaf, in search of it's next meal.

A garden snail on a bergenia leaf, in search of it’s next meal.

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