cultivation.

On this page, you will find some very basic information you need in order to cultivate espaliered trees. If you would like to access more in-depth information, please see our Other Resources page.

This page covers basic information about pollination, bloom requirements, chill concerns, rootstock basics and the USDA Hardiness Zones .

Pollination

In general, we have grouped our pollination scheme into three different categories:

1. "Required": Many fruit trees require another nearby fruit tree to provide pollen in order to produce fruit. Usually, the two trees must produce the same type of fruit (i.e.; apples and apples) but different varieties (i.e.; Fuji and Gala). Trees that fall into the category of "requiring" pollination both require another tree's pollen to fruit, and provide pollen to that other tree, in turn enabling it to fruit.
Furthermore, the two trees must bloom at around the same time of the season: early, middle or late. A tree that blooms early can be paired with one with an mid-season bloom, but not with a late bloomer. By the same token, a late bloomer can cross-pollinate a mid-season bloomer but not one that blooms early.
Two trees that bloom at around the same time and both require a pollinator should complement each other beautifully; that is, should enable each other to produce fruit annually. Please be aware that these trees must be planted at minimum within the same acre, although closer is better.
Examples of fruit trees that "require" pollination: Cox's Orange Pippin Apple and Comice Pear.

2. "Self": Some fruit trees can accept their own pollen, which means that in general, they do not require another variety's pollen in order to fruit. However, gardeners should be aware that sometimes the fruit is more abundant with a pollinator.
Fuji Apple is an example of a self-pollinating variety.

3. "None": Trees falling into this category require another pollinating variety that blooms at the same time of season, planted nearby. However, unlike trees in the "require" category, these trees themselves produce sterile pollen, and so will not have a reciprocal relationship with the other tree, nor will they pollinate themselves. In order for both trees to fruit, the other tree in this pair must be self-pollinating.
Gravenstein Apple is an example of a non-pollinating, or sterile, variety.

Bloom

"Bloom" refers to the time of season in which the variety produces blossoms: early, mid or late. As pollen comes from flowers, when matching trees for cross-pollination purposes, it is important to choose two trees with the same bloom times to ensure that pollination occurs.

Chill

Apple and pear trees require cold winters to produce properly. To determine how much cold a fruit tree needs, we use the "chilling requirement" standard, which is measured by the number of winter hours below 45 degrees Farenheit a tree requires to fruit properly. Trees with a "low chill" requirement need less cold than others - 550 chilling hours or less, depending upon the variety. Please see the section on the USDA zones to get a sense of the chilling requirement in your area.

Rootstock

The lower portion of your fruit tree is the "rootstock," upon which your tree has been grafted. Different rootstocks have different characteristics in terms of chilling requirements and disease resistance. We tend to use a "dwarf" rootstock on most of our espaliers, which limits the vertical growth of the tree.

USDA Hardiness Zones

Click here to see larger map.

California: Click here to open a close-up map of California's zones in a new window.

Visit the website of the U.S. National Arboretum to see a more detailed map of the US Hardiness Zones.