Glossary
Alternate: Alternating leaf placement as opposed to opposite leaf placement on a stem.
Annual: Plants that go through a complete life cycle, including germinating, growing, flowering, seeding, and dying, all within one growing season.
Auxin: Chemical compounds or hormones that promote growth in plants.
Axil: The upper angle of where a leafstalk joins a stem or branch.
Bark: The outermost layers of stems, branches, and trunks of trees and shrubs.
Bark ridge: A raised bump or fold of bark on the upper side of a branch where the branch joins the trunk.
Branch: A secondary or lateral shoot or stem growing off a major stem or limb.
Branch collar: A swollen ring of bark on the lower side of a branch that connects the branch to the trunk or parent branch.
Bonsai: An artistic form of growing a dwarf plant in a shallow pot or tray.
Broadleaf: Evergreen trees and shrubs that produce blossoms and fruit.
Bush: Also known as a shrub, a woody plant with several stems rising from the base and lacking a single trunk.
Cambium layer: Behind the phloem, a thin layer of active tissue that produces new phloem cells on one side and new xylem cells on the other.
Canopy: The leafy cover or crown formed by the upper branches of a tree.
Central leader: The central stem of a tree, which is a continuation of the trunk and from which scaffolding or main branches grow.
Conifer: An evergreen tree or shrub that bears cones and has needle-like leaves.
Coppicing: The act of cutting a tree or shrub down to the ground and allowing multiple stems to grow in place of a trunk.
Cork cambium: The layer of cells under the bark responsible for creating new bark.
Crown: The canopy of a tree, including the branches, leaves, and reproductive systems growing off the trunk, and also where the roots and stem meet at soil level.
Crown raising: Removing the bottom limbs of a tree or shrub to “raise the skirt” or crown in order to create space under the tree or shrub.
Crown thinning: The thinning of branches throughout the tree or shrub to allow more light and air to circulate the center of the plant.
Crown reduction: Thinning out the tree or shrub branches so the size of the plant reduces; also known as drop-crotching.
Deadheading: Removing flowers that have already bloomed from a plant in order to prevent seed formation so it will form more blooms the following year.
Debudding: Pinching off buds of a plant to create fewer but larger blooms the following year.
Deciduous: A tree or shrub that drops its leaves each year, normally in fall or winter.
Drop-crotching: See crown reduction.
Epicormic sprouting: Shoots that grow on the main stem, trunk, or branches.
Espalier: A plant trained to grow in a two-dimensional form, normally against a wall, fence, or trellis.
Ever-blooming: A flowering plant that blooms several times in one year.
Evergreen: A broadleaf or needle-leaf tree or shrub that keeps its leaves year round.
Grafting: Joining two or more plants so they will grow as one plant.
Hair roots: Smaller roots that grow from established plant roots.
Hard pruning: Cutting back a shrub’s growth to the ground or leaving just stubs.
Heartwood: Dead tissue that, along with sapwood, is part of the innermost layer that trees and shrub depend on for support.
Hedge: A row of shrubs or low growing trees planted to form a fence or barrier.
Hedgelaying: The process of grafting a hedge to another hedge to form a barrier.
Knot garden: A formal garden made up of tightly sheared shrubs that, when viewed from above, appear to weave around each other, creating the appearance of a Celtic knot.
Lateral: The branches on the sides of a tree.
Leader: The main stem that grows from the trunk of a plant from which other branches grow.
Lion tails: Tufts of foliage and branches at the ends of main branches caused by removing all the inner lateral foliage and branches, which if not removed can cause sun scalding on the branches and trunk of a tree.
Modified central leader: The training of a young tree that combines a central leader form with an open center form.
Needle-leaf: Evergreen trees or shrubs that have leaves like needles.
New wood: Stems and branches that grow during the current growing season.
Node: The point where a leaf attaches to a stem.
Old wood: Stems and branches that grew during the previous year’s growing season.
Open center: The training of a young tree to have a vase shape with three or four branches growing outward and upward from the trunk.
Ornamental: Plants that are either dwarf-sized trees, normally in pots, or pruned in a decorative fashion as part of a garden setting.
Phloem: The layer of cells behind the cambium layer on a trunk that conducts food from the leaves and moves it to the roots or other areas of the plant that need food.
Photosynthesis: The process of a plant using sunlight shining on the leaves to create a simple sugar to use as food and energy.
Pinching: Removing the tip of a growing shoot with your finger and thumb or fingernail.
Pleaching: Weaving branches of two or more trees together to form a living wall, roof, or tunnel.
Pollarding: Cutting off or stubbing back all the growth of a tree to the same point on a branch or trunk in order to sprout new growth during the growing season.
Pruning: The act of clearing vegetation from a plant to remove diseased tissue, stimulate growth, increase fruit or nut production, or control the space that a plant occupies.
Random branching: The growth pattern of a needled conifer where branches sprout up anywhere along the trunk and branches so the conifer grows in spurts during the growing season.
Renovation: To revitalize or renew an old or neglected plant.
Root crown: The transitional area at the surface of the soil where roots turn into woody stems as they grow from the ground.
Root graft: The thickened offset area at the base of a single tree trunk or bush where a type of root system with favorable characteristics is grafted to a plant with other desirable characteristics.
Root pruning: The cutting back of the roots of a plant in order to prepare a plant for transplanting, to slow the growth of a plant, to force blooms and fruit production, or to keep a container plant healthy.
Sapwood: Part of the xylem where water and nutrients flow upward to the top of the tree or shrub.
Scaffold branches: The major branches of a tree.
Shear: To do light pruning with various tools called shears to cut, clip, or remove small branches, stems, and water sprouts.
Shoot: An actively growing stem.
Shrub: Also known as a bush, a woody plant with several stems rising from the base and lacking a single trunk.
Standard: A tree or bush trained to have a clear trunk and a leafy or rounded bushy head.
Spur: A stubby flowering branch that grows slowly.
Suckers: Shoots that grow from the base of a tree or shrub.
Topiary: A tree or shrub pruned to create a shape or sculpture.
Transpiration: The process of excess water evaporating from pores on the underside of leaves.
Tree: A perennial woody plant that grows an average of 15 feet or more, marked by a distinct main trunk with branches growing out of the sides of the trunk.
Vine topiary: The process of allowing a vine to grow on top of a topiary tree or shrub.
Water sprout: A vigorously growing shoot that grows from a branch or trunk of a tree.
Whip: A young tree that consists of an unbranched single stem.
Whorls: An arrangement of three or more leaves or petals growing from a single node.
Whorled branching: Conifers that have branches growing in whorls at intervals along the trunk or stems with few latent buds or dominant growing points on the leafless parts of the branch.
Xylem: The entire inner part of the woody structure that is located behind the cambium layer and is the supporting and water-conducting tissue of the plant.