University of Vermont Extension 
Department of Plant and Soil Science

Anytime News Article
Dr. Leonard Perry, Extension Professor
University of Vermont

If you grow fruits, from small fruits like strawberries to tree fruits like apples, you’ll run across some specific terms or words.  Even if you just look through fruit books and catalogs, you’ll likely run across some of these.  Here are some of the most common for the tree fruits.
Looking first at the main words used to group fruits, tree fruits are one main grouping (small fruits being the other), obviously for those growing on trees.  These include fruits such as apples, peaches (and the related apricots and nectarines—basically a fuzz-less peach), plums, pears, cherries, and nuts. 
For growing tree fruits, pruning is a main cultural practice and there are some terms you should know associated with them.  The two main types of pruning cuts are “heading” and “thinning”.  Heading cuts are those removing a branch tip, which stimulates growth from below the cut making a tree more bushy and dense.  Thinning cuts are those in which a whole branch is removed from where it originates, such as at the trunk.  This type of cut is used when more growth isn’t desired, to remove crossing or rubbing branches, or if more space is needed within a tree for sunlight and air circulation (which, in turn, reduces diseases). 
Just the word “thinning” will be seen applied to fruits, meaning that some are removed.  While growers may use chemicals or mechanical means for this, home gardeners do this by hand.  Trees tend to produce many more flowers, and so fruits, than they need or can support.  You might say this is to “hedge their bets”, so if these don’t thin with many dropping naturally (“June” drop), you’ll need to thin the fruits for best size and harvest, and so the branches don’t break under too much weight.   This is particularly important for apples, peaches, pears, and plums.  You may need to remove up to 80 percent of fruits, so that each is about 6 inches from the next (4 inches for plums), with only one fruit left in each cluster.
The other important pruning terms to know for a particular fruit refers to how the tree will be pruned—the pruning or training style.  “Central leader” refers to keeping one main stem, the tree forming more a Christmas tree or cone shape.  If this central leader is pruned after several years of growth, allowing an upper sideshoot to develop into a leader, this is termed “modified central leader.”  This is done to keep vigorous trees more under control, and to keep branches lower and so easier to harvest.  The “open center” is just that, and produces a vase-shaped tree.  This is used on spreading trees, particularly peaches and their relatives.
Another set of important terms for fruit trees involves their propagation.  Most are “grafted”, the desirable cultivar on the top (the “scion”) being attached through one of several means to the “rootstock” or “understock” on the bottom.  While the scion is the name you recognize and produces the fruit you desire such as ‘Liberty’ or ‘Delicious’ apple, the rootstock affects such traits as ability to grow in poor soils, hardiness, disease resistance, and size.

An example of a rootstock for apples you may not have heard of is the MM.111 rootstock (named for the Merton and Malling research centers in England that developed it).  It is drought resistant and tolerates wet soils too, resists wind so may not need staking, and resists the fire blight disease.  While experienced growers can mix and match cultivars and rootstocks, usually you don’t need to worry with this as the grower already has made good choices.

Rootstock, as mentioned, affects tree size and so brings up another set of terms.  “Standard” trees are usually not grafted and grow to their normal size, which may be 30 feet or more for apples (often less in cold climates and a less than ideal site).  Obviously such a large tree would be more difficult to harvest than a shorter one, and takes longer to bear fruit, but may provide a better shade tree in landscapes and may be hardier. 

More commonly seen are the “dwarf” and “semidwarf” trees, generally the result of the rootstock onto which they’re grafted.  While standard trees may start bearing fruit in 5 to 8 years, semidwarf often bear in 3 to 5 years, with 2 to 4 years for dwarf trees.  While semi-dwarf, depending on fruit and cultivar, may reach 15 feet tall, dwarf trees may only reach 10 feet tall.

A relatively new term relating to the upright shape of some cultivars, particularly apples and peaches, is “columnar” or “pillar”.  As with dwarf trees, these are good for small spaces as they are short and, in addition, only a few feet wide.  While this has been a standard shape for centuries of “espaliers” (trees trained into particular shapes such as candelabras, fans, or horizontal tiers), some new cultivars have this columnar shape naturally.  Examples of columnar apples are ‘Golden Sentinel’ and ‘Northpole’. 

“Alternate bearing” refers to some fruits (especially apples) bearing heavily in one year and lighter or not at all the next.  This can relate to both the cultivar, as well as the culture.  Improper pruning may stimulate lots of growth one year, with the tree “taking a rest” the next.

Many more useful terms, and more detailed descriptions, can be found in the Fruit Gardener’s Bible by Lewis Hill and Leonard Perry.

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