CLA CLA Plant Materials & Horticulture 1 — Questions and Answers
Question 1: Which USDA Plant Hardiness Zone covers most of the US Gulf Coast, including southern Louisiana and Mississippi?
- Zone 5b
- Zone 7a
- Zone 9a (Correct answer)
- Zone 11a
Correct answer: Zone 9a
Zone 9a (average minimum −6.7°C / 20°F) covers much of the Gulf Coast where mild winters allow subtropical plants to thrive.
Question 2: What is the botanical name for Eastern Redbud, a commonly specified native flowering tree in the eastern US?
- Cercis canadensis (Correct answer)
- Cornus florida
- Acer rubrum
- Amelanchier arborea
Correct answer: Cercis canadensis
Cercis canadensis is Eastern Redbud, known for its magenta spring flowers directly on bare branches before leaf-out.
Question 3: A plant specification calls for '3" Cal.' What does 'Cal.' indicate on a plant schedule?
- Height in feet
- Caliper (trunk diameter) measured 6 inches above grade (Correct answer)
- Container size in gallons
- Canopy spread in feet
Correct answer: Caliper (trunk diameter) measured 6 inches above grade
Caliper refers to the trunk diameter of nursery trees, measured 6 inches above the ground for trees up to 4-inch caliper.
Question 4: Which soil pH range is generally considered optimal for most landscape plants?
- 4.0–5.0
- 5.5–6.5 (Correct answer)
- 7.5–8.5
- 8.5–9.5
Correct answer: 5.5–6.5
Most landscape plants grow best at pH 5.5–6.5 where nutrient availability is highest and soil biology is most active.
Question 5: What does the term 'B&B' mean when specifying trees on a planting plan?
- Branch and bark condition
- Balled and burlapped (Correct answer)
- Bare and bounded
- Bundle and boxed
Correct answer: Balled and burlapped
Balled and burlapped (B&B) trees are field-grown with a soil root ball wrapped in natural burlap for transplanting.
Question 6: Which plant characteristic is described as 'stoloniferous'?
- Produces aerial roots
- Spreads by horizontal above- or below-ground runners (Correct answer)
- Has needle-like leaves
- Tolerates full shade only
Correct answer: Spreads by horizontal above- or below-ground runners
Stoloniferous plants produce stolons — horizontal stems (above or at soil level) that root at nodes to spread vegetatively.
CLA CLA Plant Materials & Horticulture 1
Which USDA Plant Hardiness Zone covers most of the US Gulf Coast, including southern Louisiana and Mississippi?