The season has arrived to transplant trees

September and October are the best months to plant or transplant trees in our climate. Milder fall temperatures reduce transplant stress and root systems have at least two months to become established before cold winter weather slows growth. This week we’ll go over tips on choosing a tree; next week we’ll review planting and staking trees.

Before buying or transplanting a tree, check the Fresno County Master Gardeners website, www.ucanr.edu/sites/mgfresno, for downloadable lists of evergreen and deciduous trees suitable for our planting zones (Zone 7 in the foothills, Zones 8 and 9 in the Valley). Lists of trees suitable for small spaces and for really small spaces are also available on the website. A little research can help you find the right tree for any space in your garden. The Master Gardeners tree shopping lists describe tree shapes, allergy levels, litter problems, size at maturity, flower and leaf color, water needs and whether the trees are fast- or slow-growing.

Many new housing developments have very limited yard space. When choosing your planting spot, keep in mind that most trees should be planted no closer than 12 feet from buildings, fences and other structures to mitigate any possible root damage to them. If planting a tree under or near power lines, make sure the tree’s height and canopy size at maturity will remain small enough to avoid touching the lines.

No tree is problem-free, but wise choices will alleviate future aggravation. Some trees (liquid amber, Southern magnolia, ornamental plums, even evergreen redwoods) drop a lot of litter that can twist an ankle, stain the patio or clog the pool filter. Trees with invasive roots (Chinese tallow, now considered an invasive species) can alienate your neighbors. Some trees are prone to pests (crape myrtle aphids) or disease problems (sycamore anthracnose, fireblight in ornamental pears). Disease-resistant cultivars are often available; read labels carefully and quiz nursery staff.

Evergreen trees will provide shade all year long; deciduous trees that lose their leaves in fall provide cooling shade in spring and summer and let light and heat into a house in fall and winter. Both types help save energy when planted on the south or west sides of a house. Use a tall stick to estimate where tree shadows will fall (best done in late June/July when the sun is at its highest point in the sky and temperatures are highest) and try to plant in a spot that creates late afternoon shade.

After you’ve narrowed your tree choices down, visit nurseries and garden centers to check out the fall leaf color on deciduous trees as well as the quality of the stock. Choose trees that have a straight, sturdy trunk and a well-balanced branch structure with many branches spaced evenly around the trunk. In order to save space, some nurseries and garden centers trim off lower branches on their trees to create a lollipop tree head. Trees that still have their lower branches carry more leaves (leaves make food for trees) and tend to grow faster. The lower branches can be pruned off in a few years if they become obstructions.

This story was originally published September 8, 2016 at 12:46 AM with the headline "The season has arrived to transplant trees."