CGM Horticulture Practices & Plant Health 2 — Questions and Answers
Question 1: Which pruning technique involves removing a branch back to its point of origin at the trunk or parent branch?
- Heading cut
- Thinning cut (Correct answer)
- Stub cut
- Drop-crotch cut
Correct answer: Thinning cut
A thinning cut removes a branch entirely back to its point of origin, maintaining natural branch structure and promoting airflow.
Question 2: What does the term 'hardening off' refer to in horticulture?
- Applying dormant oil to woody plants
- Gradually acclimating greenhouse-grown plants to outdoor conditions (Correct answer)
- Adding lime to lower soil pH
- Freezing seed stock to improve germination
Correct answer: Gradually acclimating greenhouse-grown plants to outdoor conditions
Hardening off gradually exposes plants to outdoor temperature, light, and wind fluctuations before transplanting to reduce transplant shock.
Question 3: A grounds manager notices yellowing between leaf veins on newly planted azaleas in high-pH soil. The most likely cause is:
- Nitrogen deficiency
- Iron chlorosis (Correct answer)
- Potassium toxicity
- Overwatering
Correct answer: Iron chlorosis
Iron chlorosis causes interveinal yellowing on acid-loving plants like azaleas when high soil pH makes iron unavailable for uptake.
Question 4: Which of the following best describes the function of mycorrhizal fungi in plant health?
- They fix atmospheric nitrogen into plant-available forms
- They extend root surface area to improve water and nutrient uptake (Correct answer)
- They produce plant hormones that stimulate shoot growth
- They decompose organic matter into humus
Correct answer: They extend root surface area to improve water and nutrient uptake
Mycorrhizal fungi colonize plant roots and extend hyphae into the soil, dramatically increasing the effective absorptive surface area for water and phosphorus uptake.
Question 5: When transplanting a balled-and-burlapped tree, the planting hole should be:
- Twice as deep as the root ball and same width
- Same depth as the root ball and twice as wide (Correct answer)
- Twice as deep and twice as wide as the root ball
- Same depth and same width as the root ball
Correct answer: Same depth as the root ball and twice as wide
Planting holes should be the same depth as the root ball but two to three times wider to allow roots to establish in loosened soil without settling below grade.
Question 6: The practice of applying a 2–4 inch layer of organic mulch around trees primarily benefits plant health by:
- Increasing soil temperature in summer to speed growth
- Conserving soil moisture and moderating soil temperature (Correct answer)
- Preventing all weed seed germination permanently
- Adding significant macronutrients directly to roots
Correct answer: Conserving soil moisture and moderating soil temperature
Organic mulch conserves soil moisture, moderates temperature extremes, and suppresses weed competition, creating favorable conditions for root growth.
Question 7: Which cultural practice best reduces the spread of fungal diseases on turfgrass?
- Mowing at the lowest recommended height daily
- Watering in early morning so foliage dries quickly (Correct answer)
- Applying high-nitrogen fertilizer in late summer
- Core aerating every two weeks during the growing season
Correct answer: Watering in early morning so foliage dries quickly
Early-morning irrigation allows foliage to dry quickly during the day, reducing the prolonged leaf wetness that fungal pathogens require to germinate and infect.
CGM Horticulture Practices & Plant Health 2
Which pruning technique involves removing a branch back to its point of origin at the trunk or parent branch?