Nursery and stock selection

Key terminology

The following is a list of key terminology for understanding and working with planting stock as a Landscape Architect. Terminology is verbatim from the Canadian Nursery Stock Standards 9th edition (2017).

Balled and Burlapped (B&B): Plants established in the ground that have been harvested by digging with a soil ball so that the soil within the ball remains undisturbed. As part of the harvesting process, the soil ball is bound in burlap or similar mesh material.

Bare Root (BR): Plants harvested while dormant without a ball of soil or from which the growing medium has been removed.

Caliper: The above ground diameter of a distinct part of a nursery stock stem, measured in accordance with this Standard. The location of measurement depends on the type and size of plant. Measurement height begins at the ground level, soil line or root flare, as appropriate. The word may be abbreviated as cal.

Container: The pot in which nursery stock is grown or sold. Containers are manufactured of different materials such as plastic, wood, paper, cloth, natural fiber, etc. and may vary greatly in size, shape, and quality. However, in the context of nursery stock, containers are not used as a final installation for growing, as for example, in a landscape planter.

Cultivar: Cultivated plants that are specifically named, whose unique characteristics are retained during propagation, and populations are maintained by human efforts. They are distinguished from botanical varieties which also are distinct populations of plants in a species, but are naturally occurring.

Graft: A product of asexual propagation where two plants or plant parts are joined together so that they will unite and continue their growth as one.

Live stake: long cuttings taken from hardwood species that are driven into the ground to take root and typically Salix (willow) species or Cornus (dogwood) for restoration projects. (From University of Washington).

Plug (PL): A cylinder of medium in which a plant is grown. The term is generally used for seedlings and rooted cuttings that have been removed from the container with the medium held intact by the roots.

Rooted Cutting (RC): A vegetative portion, either hardwood (HWC) or softwood (SWC), removed from a parent plant that has been induced to form roots and eventually new leaves and shoots.

Canadian Nursery Stock Standards

The Canadian Nursery Stock Standards 9th Edition provide a consistent set of specifications and standards for landscape architects to comply for planting plans. The following information is a key summary of specifications outlined in the standards pertaining to planting stock for landscape architects practicing in Canada to be aware of.

  • Container grown stock
  • Lining out stock (includes all plant material suitable to transplant for growing on to a desired size.)
  • Evergreen and deciduous conifers
  • Broadleaf evergreens
  • Deciduous shade and flowering trees
  • Deciduous shrubs
  • Roses
  • Fruit tree selection, including small fruit shrubs, understock, and vegetatively propagated plants.
  • Vines and ground covers
  • Herbaceous perennials and ornamental grasses
  • Bulbs, corms, and tubers
  • Christmas trees
  • Nursery turfgrass sod
  • Compost

Specifying trees

Resource for infographic showing how long it takes a nursery tree to reach maturity.

Trees are measured at the nursery by caliper size and should be measured 15 centimeters above ground level for trees up to 10 cm. Anything larger should be measured 30 centimeters above ground level and for trees larger than 30 mm, caliper should be measured at 1.3 meters above ground level.

Measuring a tree using a caliper tool. Caliper measurements are also used to measure trees for timber harvesting and fuels.

The following Canadian Nursery Stock Standards highlight key criteria by tree type:

  • Evergreen and deciduous conifers: designated by dwarf (under 100 cm height at maturity), medium (200 cm height at maturity), tall and columnar where width shall not be less than 20% of height, and tall and broad where width shall not be less than 40% of height.
  • Broadleaf evergreens: classified as spreading (less than 30 cm in height), semi-spreading (height should be half the spread, globe and dwarf (spread not less than 2/3 of the height), and upright (spread not less than 1/3 of the height).
  • Deciduous shade and flowering trees: classified as dwarf, formal, and top-worked (grafted) up to a maximum height of 600 cm, standard (measured by caliper from 20-35 mm), small spreading ( stem 30 cm to 80 cm), columnar and fastigiate, and multi-stemmed.

Pot sizes

Typical pot sizes found at nurseries include:

  • #1: 1 gallon of soil, diameter of approximately ~7 inches and a height of ~7 inches.
  • #2: 2 gallons accomodates growing and maturing. Diameter of around ~8.75 inches and a height of ~7 inches.
  • #3: 3 gallons ideal for creating an immediate impact while allowing plants to mature fully. Diameter of approximately ~11 inches and a height of ~9.62 inches.
  • #5: 5 gallons commonly used for more extensive, instant-impact goods like mature shrubs and fruit tree varieties. Diameter of about ~10.75 inches and a height of ~11 inches.
  • #7: 7 gallon accomodates various varieties of larger perennials and hardy plants. Diameter of ~14 inches and a height of ~11.5 inches.
Example in practice:
NATS Nursery is wholesale native plant nursery serving the Metro Vancouver region. In their nursery catalog, they specify the following plant codes.
C= container; P= plug; LS= live stake; URC= unrooted cuttings
Plants are offered in varying sizes dependent on their growing habit. For example, Aquilegia formosa (red columine) is offered as plugs (P) and in containers (C) but Cornus sericea (red osier dogwood) is also offered as LS (live stake) for large-scale restoration projects.

Cedar shrubs in balled and burlapped wire baskets will require removal of basket and burlap at time of planting. Dogwood shrubs are in #5 pot size.

Nurseries in the Metro Vancouver region

The following are recommended nurseries in the Metro Vancouver region, specializing in native plants to the Pacific Northwest, perennial selection, or a wide range of tree stock.

  1. Nat’s Nursery – The Township of Langley, BC – specializing in wholesale native plants of British Columbia, including green roof plantings, and large tree and perennial stock.
  2. Phoenix Perennials – Richmond, BC – rare specialty perennials, native plants, and ground covers.
  3. Coast Salish Plant Nursery – Maple Wood Flats, North Vancouver, BC – supplies native plants for habitat restoration projects with all proceeds supplied to repair relations with Tsleil-Waututh, Coast Salish peoples, and with the land.
  4. Environmental Youth Alliance Plant Nursery – Vancouver, BC – grown by local youth, provides young native plants at reduced or no-cost to local community groups (e.g. community gardens) and provides an annual native plant sale.
  5. Plan Bee Native Plants – Langley, BC – aims to help pollinators and wildlife through the sale of native plants to British Columbia.
  6. Cedar Rim Nursery – Langley, BC – large wholesale nursery and tree stock provider, specializing in ornamental tree and perennial stock.
  7. Linnaea Nurseries – Langley, BC – wholesale plant nursery specializing in hardy nursery stock and native plants to the Pacific Northwest.
  8. Hutchinson Nursery – Langley, BC – supplier of native plants, evergreens, shrubs, perennials, ground covers, and large specimen trees.

The role of the landscape architect

Landscape architect Michael Keenen, Chair of the ASLA, expressed key actions landscape architects can take to get to know the nursery industry and to collaborate in creating successful relationships between industry professionals. This section was adapted from the 2019 ASLA article, Time to Grow Up: The Landscape Architect-Nursery Grower Relationship.

  1. Visit local nurseries with your firm or in school to learn how trees, shrubs, and plants are grown and what is available in stock.
  2. Invite growers to visit you through lunch and learns and webinars.
  3. Know your suppliers by visiting industry shows and attending conferences.
  4. Plan ahead to anticipate shortages well in advance of planting dates.
  5. Consider contract growing through the early stages of a project to ensure plants are available when you need them.