Roadside Revegetation

IMPLEMENTATION GUIDES
Container Design – Container shape is also an important consideration in stocktype selection
because it determines how easily the root plug is extracted from a container, the degree of root
spiraling, what planting methods are used, and ease of handling. The depth and taper of the
container walls govern how easily a root plug can be extracted from its container. Generally,
the greater the taper, the easier a root plug can be extracted from its container. Taper becomes
more critical as container walls become longer with respect to the diameter of the opening.
Straight- walled “tall pots,” made from PVC pipe, are very long in comparison to the diameter
of the opening. Root plugs from this container are difficult to extract without the placement
of Vexar tubing inside the container. Pulling the Vexar tubing during extraction brings out
the entire root plug without undue stress to the stem or root system. Other nurseries offer
tall pots with the PVC pipe cut in half lengthwise and held together with electrical ties. Before
planting, the ties are cut, which allows easy access to the root system.
Several container design features affect root development and plant quality. When plant roots
grow out and hit the sides of the container, they often grow downward in a spiral pattern.
When roots reach the bottom holes, they should “air prune.” In poorly designed containers,
the circling roots will eventually form a tight mesh which, after outplanting, can continue to
circle and “strangle” the plant. Most containers have vertical ribs that guide roots down the
sides of the container walls to prevent root spiraling. Some smaller containers feature copper
coating on their walls to chemically prune the roots as they grow. Other container walls have
vertical air slits which air prune the roots. When container roots are so cultured, the root system
is more fibrous with more root tips.
Root condition is a critical factor to discuss at the time that growing contracts are being
developed. Roots that have excessive spiral growth must be pruned before they are planted.
This is most easily done at the nursery during harvesting. This extra processing step must be
stipulated in the growing contract.
Matching Nursery Plants to Outplanting Site – A wide variety of nursery stocktypes are
available (Figure 10-80). Site factors should be considered before placing an order. The depth
and width of containers are very important for seedling survival and growth. Sites with low
precipitation during spring, summer, and fall should be planted with larger container sizes.
Where soil moisture-holding capacities are low or vegetative competition for soil moisture is
high, long containers should be considered. Where rock content is high and it is hard to excavate
a planting hole, shorter container stocktypes should be used. Additional post- planting care
must be implemented to compensate for shorter roots (see Section 10.3.4, Installing Plants).
The planting method dictates the size of the root plug. For instance, the expandable stinger
and power augers require plug diameters no greater less than 4 inches. Large seedling stems
and tops are required where animal damage is expected.
Stocktype selection often determines seedling survival rates and how fast they grow in the first
years after planting. Typically the larger the root system, the better the survival and growth.
Larger stocktypes cost more, so it is important to target the stocktype to the needs of the
site and revegetation objectives. For instance, if quick establishment of vegetation for visual
screening is an important objective, then a large stocktype would be ordered. On the other
hand, if a revegetation unit is relatively unseen and the site has few limitations to plant survival,
a small, less expensive stocktype would be ordered. While larger stocktypes are generally
more expensive than smaller stocktypes, the total costs of establishing seedlings should be
considered before settling on a smaller plant. Costs for replanting a site where smaller seedlings
died in the first year can be far more expensive than planting larger plants in the first place.
Years in the Nursery – Bareroot stocktypes are often defined by the years they are grown at
the nursery, whereas container plants are typically described by the size of the container. This
is important when ordering plants because many species take longer than one year to grow
to the desired plant size. If plants are needed for a project within one year, the revegetation
specialist will need to order smaller size containers to assure that the roots can fill the plug.
RL Supercell
D16 Deepot
Short One Treepot
Tall One Treepot
2 Gallon Treepot
PVC Tallpot
Ball-and-Burlap
Figure 10-80 | Match stocktype to
site conditions and planting method
Nurseries can produce plants in all
shapes and sizes. The best stocktype
for your project will depend on site
conditions and time and method of
planting.
Roadside Revegetation: An Integrated Approach to Establishing Native Plants and Pollinator Habitat
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