Horticulture Principles and Practices

19.16.1 CANE FRUITS
Cane fruits are temperate fruits and include raspberry, blackberry, and hybrid berries
(e.g., boysenberry, sunberry, and tayberry). They bear their fruits on long canes. These
cane fruits, sometimes called brambles, are pruned in summer or winter to remove all
of the canes that fruited in the previous season and any unwanted canes and suckers.
An important consideration, in all pruning operations, is knowing where fruits will
be borne on a plant. Some species, including many brambles, bear their fruits on canes
produced in the previous season. Pruning removes all of the canes that fruited in the previous
season. Pruning is also done in summer or winter when the plant is dormant. Also,
weak canes and broken branches are cut off. Under such circumstances, plants must be
pruned judiciously such that enough buds are left from the current season’s growth for
production in the next season.
Cane fruits can be trained on trellises or on a fence or wired wall. Fruiting and new
canes occur simultaneously. Once harvested, the fruited canes are removed so that the
new canes can be positioned for fruiting in the next season. The goal of pruning is to
ensure that year-old canes are in position each season. Pruning of individual species differs
slightly.
Brambles
The collective name for the
fruits in the genus Rubus.
19.16.2 BUSH FRUITS
Popular bush fruits include currant (black, red, and white), gooseberry, and blueberry. The
goal of pruning these crops is to remove older and less productive wood to allow new and
more vigorous shoots to grow. Horizontally growing wood is removed and the bush
thinned to avoid overcrowding and improve circulation of air. This aeration decreases disease
incidence. Black currant (Ribes nigrum) is produced as a “stooled” bush whereby the
old wood is cut back close to the ground to allow a set of new shoots to develop. The highbush
blueberry (Vaccinium corymbossum) can remain productive for a long time, and thus
removing fruited wood is not necessary for several years.
19.17 PRUNING ORNAMENTAL PLANTS
19.17.1 PRUNING CONIFERS
Conifers are cone-bearing plants. They may be low growing, as in prostrate junipers, and
useful as ground covers. Some conifers are used as hedge plants.
Ground Covers and Hedges
Conifer hedges require pruning to maintain the desired shape, whereas ground covers seldom
need it. Conifers have different branching habits. Some plants branch only once a year
(as in pine, spruce, and fir), starting with the beginning of the season’s growth. This growth
pattern results in circular (whorl) growth of branches at the growing tip. These plants lack
latent buds on old wood and as such will not regrow when cut back severely. The candles
(new growth) on the whorls may be shortened or pinched back while the needles are small
to control growth (Figure 19–25). Junipers, on the other hand, branch as growth proceeds
and produce fresh growth at the point of pruning. Junipers may be thinned or sheared.
Pruning Coniferous Trees
Coniferous trees commonly develop a single dominant central axis with an overall narrow
pyramidal shape. This shape makes it impossible to shorten a mature plant without
destroying its natural look. Some conifers such as junipers and digger pines have multiple
central leaders and are more tolerant of height reduction. Conifers are amenable to
pruning to fit symmetrical shapes. When pruning conifers, one should always cut back
to visible buds and leave no stocks. Conifers tend to grow low branches. Pruning of some
19.17 Pruning Ornamental Plants 601