Shrubs : Overall Height/Spread
General
The overall height and/or spread, at the time of sale, is significant in the specification of shrubs, although this is now additionally qualified by reference to the number of branches (or breaks) which is to be expected for the plant of that size. Shrubs vary from compact, slow growing species, to low forms, through medium size types to vigorous, fast growing species and it is important to specify appropriately for each type.
The use of height and/or spread dimensions depends on the characteristics of the species and the dimensions which are most appropriate at the time of sale. The following tables give information about the general grades for shrubs in cultivation.
Bare Root Shrubs
Compact, low, medium and vigorous species/cvs
Figure 1:
BARE ROOT SHRUB
| Height in cm |
| 20-30 |
| 30-40 |
| 40-60 |
| 60-80 |
| 80-100 |
| 100 + |
Bare Root Balled Shrubs
Low/compact : Height or spread in cm
10-15 |
30-40 |
70-80 |
150-175 |
15-20 |
40-50 |
80-100 |
175-200 |
20-25 |
50-60 |
100-125 |
200-225 |
25-30 |
60-70 |
125-150 |
225-250 |
e.g. Cotoneaster 'Coral Beauty'; Genista lydia; Potentilla 'Elizabeth'
above 250 in 50 cm steps, above 400 in 100 cm steps.
Medium : Height or spread in cm
15-20 |
40-60 |
100-125 |
175-200 |
20-30 |
60-80 |
125-150 |
200-225 |
30-40 |
80-100 |
150-175 |
225-250 |
e.g. Berberis thunbergii, Cytisus scoparius; Escallonia 'Slieve Donard'; Euonymus alatus
above 250 in 50 cm steps, above 400 in 100 cm steps.
Vigorous : Height or spread in cm
20-30 |
40-60 |
100-150 |
200-250 |
30-40 |
60-100 |
150-200 |
250-300 |
|
|
|
300-400 |
e.g. Cotoneaster 'Cornubia'; Elaeagnus x ebbingei; Hippophae rhamnoides; Hydrangea paniculata
above 400 in 100 cm. steps
Ground cover : Spread in cm
10-15 |
20-(25) |
30-40 |
50-60 |
15-20 |
(25)-30 |
40-50 |
60-80 |
e.g. Ceanothus thyrsiflorus repens; Cotoneaster dammeri; Euonymus fortunei cvs.
Additional factors:
Specimen shrubs :
These plants must have height and spread specified.
For genus Rhododendron the following grades apply:
Low/compact and medium : Height or spread in cm.
10-15 |
25-30 |
50-60 |
80-90 |
15-20 |
30-40 |
60-70 |
90-100 |
20-25 |
40-50 |
70-80 |
100-120 |
Vigorous : Height or spread in cm.
30-40 |
70-80 |
120-140 |
200-225 |
40-50 |
80-90 |
140-160 |
225-250 |
50-60 |
90-100 |
160-180 |
250-275 |
60-70 |
100-120 |
180-200 |
275-300 |
above 300 in 50 cm steps.
Deciduous azaleas : Height in cm.
| 30-40 |
60-70 |
100-125 |
175-200 |
| 40-50 |
70-80 |
125-150 |
200-250 |
| 50-60 |
80-100 |
150-175 |
250-300 |
Japanese azaleas : Spread in cm.
15-20 |
30-40 |
60-70 |
90-100 |
20-25 |
40-50 |
70-80 |
100-120 |
25-30 |
50-60 |
80-90 |
120-140 |
Cell Grown Shrubs
Cells are used for the production of seed raised trees and shrubs. The following height grades are used. In addition it is important to specify the CELL VOLUME and the minimum ROOT COLLAR DIAMETER in specifying cell grown shrubs.
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Figure 2: CELL GROWN SHRUB
(Corylus avellana)
| Overall height (cm) |
Volume |
Root collar dia. |
| 10-20 |
50 cc |
4 |
| 20-40 |
100 cc |
4 |
| 40-60 |
150 cc |
6 |
| 60-80 |
200 cc |
8 |
Typical Overall Height Grades
All forms of shrubs are supplied in containers. The following are the typical OVERALL HEIGHT grades used for the supply of container grown shrubs. The actual grade is determined by cultural conditions and the characteristics of the species/cv.
Figure 3: CONTAINER GROWN SHRUB
(Cytisus x praecox 'Warminster')
| Overall Height in cm: |
| 10-20 |
| 20-30 |
| 30-40 |
| 40-60 |
| 60-80 |
| 80-100 |
Typically the height is specified except for compact/low growing shrubs or ground covers where spread is specified.
For Specimen shrubs both height and spread may be specified.
Typical Overall Spread Grades
Typically the spread grade is specified for compact/low growing shrubs or ground covers. The following are the typical OVERALL SPREAD grades used for the supply of container grown shrubs. The actual grade is determined by the cultural conditions of the plant and the characteristics of the species/cv.
Figure 4:
SPREADING SHRUB (Stephanandra incisa 'Crispa')
| Diameter in cm: |
| 10-15 |
| 15-20 |
| 20-25 |
| 25-30 |
| 30-40 |
| 40-60 |
| 60-80 |
For Specimen shrubs both height and spread may be specified.