Glossary

A plant that completes its life cycle in one year; it grows from seed, flowers, and produces new seeds before it dies.

Refers to dormant plants that are sold without soil surrounding their roots; often used for shipping mail order plants and fruit trees

A leaf that is divided into multiple leaflets, with each leaflet further subdivided into smaller leaflets

The swollen area located where the base of a branch attaches to the trunk of a tree; pruning cuts should be made on the outside of the branch collar so they heal properly.

The time of year when plants are emerging from winter dormancy and buds are visibly swelling

The layer of cells responsible for development of new xylem and phloem, leading to an increase in girth of a woody plant

1. The crown or top portion of a tree

2. In forested areas, the top layer of growth provided by a group of trees

A collaborative plant introduction program consisting of partnerships between Chicago Botanic Garden, The Morton Arboretum, and the Ornamental Grower’s Association of Northern Illinois (OGA), designed to develop and promote the use of new plant cultivars that are well-adapted to the growing conditions of the Upper Midwest

One of the mineral components of soil

To pinch or remove faded flowers in order to tidy a plant, stop seed production, and promote future flowering

The loss or removal of leaves from a tree or shrub

A progressive death of plant tissues

A plant that is able to resist a disease that interferes with its normal growth and function

The area under the outer most edges of the branches on a tree

A plant variety that is abnormally small for a given species

2. The process of training a woody plant to grow in a flat plane, usually against a wall or trellis

Refers to a narrow tree or shrub in which the branches grow vertically upward and close together

Leaves

A level of botanical classification consisting of related species that share some basic characteristics

Physical strangulation of a branch, or the removal of bark on a branch, leading to a disruption in the flow of water and nutrients, causing dieback

Hairless

The natural shape of a tree or plant

A type of pruning in which a cut is made to reduce the length or height of a branch or stem

The outer covering of a seed or fruit

A grouping of flowers arranged in a specific pattern

Typically, a non-native plant that competes with native plants for water, nutrients and space, destroying the natural habitat and ecosystem of native species in the process; (Different from aggressive; see definition for aggressive).

One section of a compound leaf

A protruding/projecting part of a leaf margin

The edge of a leaf

A layer of material, such as woodchips or compost, that is applied on the soil surface to retain soil moisture and moderate soil temperature extremes; if organic, it will break down to improve soil structure and fertility

A dry fruit in which the seed is surrounded by a hard structure

An arrangement in which leaves or buds that are attached to opposite sides of a branch at the same node; (can also apply to the arrangement of branches)

A compound leaf with leaflets originating from a center point and radiating out in a fan-like fashion

An organism capable of causing disease

A type of pruning that encourages branching and fuller growth by removing growing tips; often achieved by physically pinching between two fingers

The process of transfering pollen from the male anther to the female stigma, either within a single flower or from one flower to another

Having hairs

An extension of the petiole on a compound leaf; leaflets are connected to the rachis

A winged seed or fruit

A region of the trunk located just beneath the bark, consisting of xylem tissue

The outer layer of floral parts, often green and leaf-like in appearance, and serving to cover and protect the unopened flower bud

A multistemmed woody plant that is shorter than a tree

The space between two lobes of a leaf

The arrangement of individual soil particles and pore space into larger units, or aggregates; soil structure affects the amount of air and water held in the soil.

A small, typically one-celled reproductive unit of nonflowering plants, fungi and algae

The support roots of a plant

A shoot that arises from the roots, with the ability to increase the size of a plant by forming a colony

A central, vertical root that penetrates deeply into the soil

The process by which water vapor is released through the leaves of a tree or plant

A type of inflorescence in which all the flower stalks originate from one point, like spokes of an umbrella

A group of plants of the same species having one or more distinguishing characteristics and occuring naturally in the wild