Growing Fruit Trees at Home by Drew Zwart, PhD

As any gardener can tell you, there are few things more satisfying than growing, harvesting, and eating food out of your own backyard. Fruit trees like apples and cherries can be a great source of nutritious and delicious produce, however if you want to harvest edible fruit from the home garden, you must remember that choosing the right variety and planting it properly is far from the last step of the process. The three major concerns for home fruit production are: disease and insect management, soil management, and pruning.

The most significant limiting factors for fruit tree production are

fungal diseases and insects with larvae that feed on fruit. Any tree fruit requires multiple applications of fungicides and insecticides. For example, even in eastern Washington, where 91% of organic apple production occurs due to hot and dry summer weather, multiple applications of copper or sulfur based fungicides are required to protect against the foliage and fruit disease known as ‘apple scab’. For cherries, organic commercial producers couldn’t even exist until an organic insecticide was registered to help manage the cherry fruit fly.

The disease and insect pressure is even greater in the home landscape for a number of reasons. First, the presence of turf increases humidity due to irrigation or the high rate of

Fire Landscaping by Drew Zwart, PhD

Plant placement is also important. Multi-tiered landscapes are problematic because the canopies of varying heights creates a ladder for fire to move from the surface up into tree canopies. In areas with a high risk of fire, plantings should not be overly dense and tree canopies should be pruned to maintain distance from the grass or groundcover. Maintaining ten feet of clearance between tree canopies and the ground vegetation is a common recommendation in fire prone areas. Trees should also be pruned in order to create space between the canopy and any structures, and all dead or dying material should be removed as this is more flammable than live tissue.

Mulch is often considered an ideal soil cover for plant health, however many mulch materials are flammable. Several studies have shown that rubber mulch and pine straw are the most flammable and result in the hottest fires and tallest flames. Shredded and dyed pallets or other processed wood products are also high risk. Composted wood chip mulch has been shown to produce the lowest intensity fires, and is recommended above any other organic mulch because it tends to smolder and rarely ignites into open flames. A thin strip of gravel between the composted wood chips and the home can greatly reduce potential for damage. ‘Green’ freshly chipped woody material is also considered lower risk.

Homes that are in the wild land–urban interface are at the highest risk from fire. The photo at right shows homes in the interface that were saved from a brush fire due to low density plantings and the creation of a vegetation-free strip by plowing. When creating vegetation-free strips is not an option, plant selection, sparse planting, and consideration of mulch materials becomes very important.

Low density plantings and a plowed vegetation-free strip saved these homes from a brush fire.

Most of California experiences distinct wet and dry seasons, often referred to as a ‘Mediterranean’ climate. This pattern results in very desirable weather conditions, however it can also lead to high risk of fire at the end of the dry season. In addition, three years of below average rainfall has resulted in extremely dry conditions with high risk of fire from Southern California all the way through the San Francisco bay area.

One strategy for protecting homes from wildfire involves creating and maintaining a fire-wise landscape. Species selection and plant placement will have major implications for fire safety. For example, many species are known to be highly flammable, or to create conditions that favor fire through shedding of leaves, bark, or branches, or due to high oil contents. Eucalyptus species are a prime example of a terrible landscape plant when considering fire. These trees are dense with flammable oils and burn extremely quickly and at high heat. In addition, the exfoliating bark creates piles of flammable materials at the base of the trees. Other common species known to be highly flammable include most conifers (pines, firs, junipers, spruce, etc.), rosemary, manzanita, and ornamental grasses. Fire-resistant plants include many deciduous plants like maples, flowering fruit trees, magnolia, and viburnum. High moisture content plants like succulents are also very fire-resistant and are ideal plants for directly adjacent to structures.

TREE TIPST R E E & S H R U B C A R E F R O M B A R T L E T T T R E E E X P E R T S

Fungal diseases and insects are the most significant challenges to fruit production.

Continued on page 3

Incense Cedar Branch Cankers by Drew Zwart, PhD

Disease Alert-

Smart Irrigation- Is It Effective?

Smart irrigation refers to the use of technology to make smarter decisions on irrigation water use. This technology usually consists of sensors that monitor weather conditions or measure soil

moisture content. The intent of either approach is to adjust irrigation run times in response to environmental conditions to efficiently use water and keep plants healthy. Many existing irrigation systems can simply be retrofitted with new technology; making use of current controllers and reducing costs.

But does it work? In most cases, yes. Depending on which study you investigate, water savings can be small or quite significant. This

variation in the studies’ findings is due to the differences in climate, plant material, system design, water delivery heads, previous irrigation scheduling, etc., but generally there can be quite a savings of water. Keep in mind, however, that during certain times of year, water use by smart systems can actually be increased over conventional systems because the previous schedule wasn’t keeping up with plant demands. The technology of these systems continually improves and is becoming more affordable. There are very simple things you can do to conventional systems to make them more efficient such as: properly installing a rain sensor, properly directing/adjusting heads, fixing leaks, installing more efficient heads, optimizing pressure, installing checkvalves, and scheduling properly.

The red turpentine beetle (Dendroctonus valens) and the black turpentine beetle

(Dendroctonus terebrans), are native bark beetles that commonly

attack pines and other conifers. They are the largest bark beetles in North America. These beetles may kill trees by tunneling under the bark or they may introduce fungi, known as “blue stain” that kills trees. As a result, turpentine beetles are unusual in that it may take only one beetle successfully boring into a pine to kill the tree.

Turpentine beetle are usually attracted to water stressed or construction damaged trees. However, healthy trees near other trees attacked by other bark beetles are also at risk.

To protect trees from turpentine beetle attack:

1. Maintain tree vigor: Avoid root and bark damage. Mulch, water and fertilize to prevent water stress.

2. Sanitation: Quickly remove dead and dying pines that are near other pines.

3. Preventative spray treatments: Have valuable pines treated several times each year to protect them from beetle attack.

In recent years in the Pacific Northwest, Incense cedars (Calocedrus decurrens) have increasingly been affected by fungal pathogens that cause branch cankers and dieback. There are two common pathogens that cause very similar symptoms on these trees. Both the fungi Seiridium unicorne and Sphaeropsis sapinea can infect branches and lead to dieback as the cankers slowly girdling the branch. While these are two distinct fungi that can be differentiated microscopically, management in the landscape is similar for both.

In the landscape, symptoms of these diseases includes whole-branch dieback, often scattered throughout the canopy or concentrated in the lower canopy. Close inspection of these branches usually reveals a sunken or gummy canker area in the transition zone between live and dead tissue. Infected branches should be pruned well below this transition because spores produced by the fungi can infect and kill other branches.

Both of these canker fungi are considered ‘stress-related’ pathogens, meaning that healthy and vigorous trees are rarely affected. Trees suffering from drought stress, over-irrigation, nutrient deficiency, root damage, or other physiological stresses have reduced defense capabilities and are therefore more prone to infection. Management of these diseases includes maintaining overall plant health through proper cultural practices such as mulching, fertilization based on soil analysis, and maintenance of proper soil moisture. In addition, preventative fungicide treatments may help reduce infections during periods of wet weather. Fungicide treatments for these diseases rarely result in 100% control, so keeping the overall plant vigor high is the best management option.

Turpentine Beetles: Dangerous Conifer Pests

by Donald Booth, PhD

A sunken or gummy canker area in the transition zone between live and dead tissue is an identifying symptom of canker fungi.

Pitch tubes of hardened sap

are the first sign of beetle attack.

Turpentine beetles usually attack pines by tunneling through the bark

near the ground.

Book ReviewsThe Holistic Orchard: Tree Fruits and Berries the Biological Way by Michael Phillips

Want to grow fruit on a small scale? This book covers basic skills about the inner-workings of the

orchard ecosystem, as well as orchard design, soil biology, and organic health management. Detailed insights on grafting, planting, pruning, and choosing the right varieties for your climate are also included, along with a step-by-step instructional calendar to guide growers through the entire orchard year.

Trees and Shrubs of the Pacific Northwest: Timber Press Field Guide by Mark Turner and Ellen Kuhlmann

This book covers 568 species of woody plants. The comprehensive field guide is great for hikers, nature lovers and plant geeks, it features introductory chapters on the native landscape and plant entries that detail the family, scientific and common name, flowering seasons, and size. Each entry includes color photographs

of the plant’s habitat and distinguishing characteristics and a range map.

Trees of Texas Field Guide by Stan Tekiela

Make tree identification in Texas easier, more informative and enjoyable!

The Trees of Texas Field Guide contains 180 species of Texas-specific trees with easy-to-use thumb tabs showing leaf type and attachment. The fact-filled pages contain the information you want to know, while full-page color photos and detailed descriptions help to make correct identification a snap!

No Paper - No Problem!Its easy to enroll in our paperless program for electronic Tree Tips. Find your 7-digit client code in the yellow box on the back page. Then, log on to www.bartlett.com/newsletter (select US), click on the registration link and sign up using your client number and postal code. If you ever want paper service again, just advise us.

Plant Focus-Wooly Grevillea, Grevillea lanigeraGrevilla lanigera is a low growing, sprawling evergreen groundcover that is great for some winter time cheer. Growing to about 4 feet tall with an equal spread the grayish green small leaves give this plant a nice texture. Clusters of dark pink fading to a cream color cover the ends of the drooping branches in profusion. An excellent plant to attract bees and hummingbirds. ‘Coastal Gem’ is a good selection readily available in the trade. It does best in full sun to part shade and great in rock garden environments or even in containers.

Fruit Trees continued from page 1

transpiration of grasses. Second, ornamental fruit trees found throughout the landscape serve as a reservoir for disease pathogens and insect pests. Diseases like apple rust are also more problematic in landscapes than in commercial orchards because the disease requires a juniper host, a plant that is common in landscapes but not typically found near orchards. Home fruit trees are also less likely to be newer varieties that have been bred for disease and insect resistance.

Soil management is also important for producing good fruit on a yearly basis. Fruit of any type represents a large pool of nutrients and carbohydrates. Harvesting fruit removes those resources from the system; therefore mineral nutrients must be replaced in the soil to

maintain available nutrients for root uptake and high rates of photosynthesis.

Pruning is another important aspect of fruit production. Fruit trees require very specialized pruning in order to maximize flowering and fruit set. The ideal pruning system varies by fruit species, and often differs dramatically from ornamental tree pruning. In fruit trees, an open, multiple-stem, low canopy is ideal for production and harvest, while these same features might lead to a poorly structured ornamental or shade tree. Each fruit has its own unique pruning requirements and there is no ‘one-size-fits-all’ approach to fruit tree pruning.

When all factors are considered, it may be easier to go to the local farm stand to fill your fruit needs. However, with a scientific approach and diligence, backyard fruit trees can be productive, healthy, environmentally friendly, and satisfying..

Apps for Tree & Shrub Indentification

The Virginia Tech Tree Identification app, vTree, brings

the award winning Virginia Tech digital dendrology material to your phone (Android or iPhone). It contains fact sheets for 969 woody plants from all over North America with an in depth description, range map and thousands of color images of leaves, flowers, fruit, twigs, bark and form.

Users can narrow the species list to any location in North America using the phone’s GPS, network signal or any entered address or zip code. Also, further narrow the species list by answering a series of very simple tree attribute questions.

Virginia Tech Tree Identification (vTree) is a free app for Android and iPhone.

Soil Care Programs by Tom Smiley, PhD

One of the basic keys to tree and shrub health is a healthy soil. Plants depend on soil for support, water and nutrients. Roots will only grow in soil that has conditions favorable for growth. 80% of all tree problems are soil related. So at Bartlett, the focus on soil management is ongoing.

There are many aspects to soil management. The simplest is soil nutrient management. This usually starts with a soil analysis followed by a fertilizer recommendation. Often the soil analysis points to the need for pH adjustment or that other nutrients besides nitrogen, phosphorus and potassium be added to the soil. A fall application or multiple applications

of fertilizer, or other amendment, are typically required every year to maintain optimum levels in the soil.

Soil compaction is a common problem after construction or where there is a lot of traffic around a tree. Soil

density can be measured. If compaction is occurring, treatments can be recommended. The simplest treatment is to mulch the soil surface with wood chips or other organic materials. If the soil is too dense to respond to mulch, Root Invigoration can be performed. This reduces compaction and promotes root development.

Beneficial microorganisms are present in most soils. Occasionally the natural microorganisms do not provide all of the benefits that the tree needs. In those cases the addition of mycorrhize or Trichoderma fungi can increase disease resistance and improve water uptake. On the topic of disease resistance, we are now providing a fertilizer that is known to increase plant resistance to the root rotting fungus Phytophthora, Verticillium wilt and some bacterial diseases.

There are many aspects to soil care for landscape trees and shrubs. These are just a few that Bartlett can assist with on your landscape.

TREE TIPS

LAB NOTES

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I’m sure you’ll find this issue interesting and useful.

Please call me if you have any concerns with your property.

published by THE F. A. BARTLETT TREE EXPERT COMPANY(877) BARTLETT (877-227-8538) in U.S. and Canada • www.bartlett.com

For Tree Tips information contact smurdock@bartlett.com© 2014 The F. A. Bartlett Tree Expert CompanyW-3