Mixed Deck — All CH Topics Flashcards

Tensiometers measure soil moisture by indicating:

Answer: Tension (suction force) with which the soil holds water

Tensiometers measure matric potential — the suction force with which soil particles hold water — which indicates how hard plant roots must work to extract moisture.

Zoysiagrass is best characterized as:

Answer: A warm-season grass known for dense, slow-growing, wear-tolerant turf

Zoysiagrass is a warm-season grass prized for its dense, wear-tolerant turf and relatively slow growth rate compared to bermudagrass.

Air layering is a propagation method best suited for:

Answer: Rooting a stem while still attached to the parent plant

Air layering wounds a stem on the parent plant, packs the wound with moist sphagnum, and wraps it to encourage roots to form before the new plant is severed.

Which soil texture typically requires the most frequent irrigation due to its low water-holding capacity?

Answer: Sandy

Sandy soils have large pore spaces that drain rapidly, holding little plant-available water between irrigations and requiring more frequent but smaller applications.

A distribution uniformity (DU) test for a sprinkler system measures:

Answer: How evenly water is applied across the irrigated area

DU compares catch-can volumes across the irrigated zone to determine how uniformly water is distributed; low DU indicates dry spots requiring over-irrigation elsewhere.

Which soil pH range generally maximizes nutrient availability for most landscape plants?

Answer: 5.5–6.5

A pH of 5.5–6.5 keeps most macro- and micronutrients in plant-available forms and is the optimum range for the majority of landscape species.

A landscape design element that provides a transition between tall trees and low ground covers is called a:

Answer: Understory layer or shrub layer

The understory or shrub layer bridges the visual and physical gap between tall overstory trees and low ground-level plantings, creating layered depth in a planting design.

What is a primary cultural practice to reduce the risk of root rot in plants?

Answer: Ensuring proper drainage in soil or containers

Root rot is a destructive plant disease caused by fungi or oomycetes that thrive in waterlogged, oxygen-deprived soil conditions. Ensuring proper drainage in soil or containers is crucial because it prevents excess water from accumulating around the roots. This allows roots to access necessary oxygen and reduces the anaerobic environment favored by root rot pathogens, thereby promoting healthy root development.

The Landscape Architect Licensure Examination (LARE) is required for professional licensure as a landscape architect, while CH certification is administered by which organization?

Answer: American Horticulture Industry Association (AHIA) / PLANET

The Certified Horticulturist (CH) credential is administered by the National Association of Landscape Professionals (NALP), formerly known as PLANET/AHIA.

Which warm-season turfgrass has the highest shade tolerance?

Answer: St. Augustinegrass

St. Augustinegrass has the best shade tolerance among commonly used warm-season grasses, making it suitable for partially shaded lawns in the South.

Seasonal color in landscape design refers primarily to:

Answer: Annual and perennial plants selected for rotating bloom periods

Seasonal color programs use annuals, bulbs, and perennials strategically rotated or selected to maintain visual interest and bloom through multiple seasons.

Compost is valued as a soil amendment partly because it improves nutrient retention. This is mainly due to its contribution of:

Answer: Cation exchange capacity via humus

The humic substances in finished compost carry significant negative charge, increasing CEC and the soil's ability to hold cations against leaching.

The cation exchange capacity (CEC) of a soil influences its ability to:

Answer: Retain and supply positively charged nutrients

CEC measures how many cations (Ca²⁺, Mg²⁺, K⁺, NH₄⁺) a soil can hold on negatively charged exchange sites, directly affecting nutrient retention.

Division as a propagation method is most commonly applied to:

Answer: Clump-forming perennials and ornamental grasses

Division splits clump-forming perennials and grasses into multiple rooted sections, rejuvenating crowded plants and quickly producing several new plants identical to the parent.

Bottom heat in propagation systems (typically 70–75°F media temperature) is used because:

Answer: Warm root zone temperatures accelerate callus formation and root initiation in cuttings

Enzymatic and cell division processes that produce roots are temperature-dependent; warm media (70–75°F) speeds rooting while cooler air temperatures reduce transpiration stress.

Dollar spot disease in turfgrass is most commonly associated with which conditions?

Answer: Low nitrogen fertility and alternating wet/dry periods with moderate temperatures

Dollar spot is favored by low nitrogen levels and periods of alternating moisture such as heavy dew or light, frequent irrigation, and can be partly managed with adequate nitrogen fertility.

Hydraulic zoning in irrigation design groups plants together based on:

Answer: Similar water requirements (hydrozones)

Hydrozoning groups plants with similar water needs on the same irrigation zone so water can be applied efficiently without over- or under-irrigating any plant.

Tissue culture (micropropagation) is preferred for propagating some plant species because it:

Answer: Produces large numbers of genetically uniform, disease-free plants rapidly

Tissue culture propagates thousands of identical, pathogen-free plantlets from tiny explants in sterile conditions, enabling rapid large-scale production of superior clones.

Which type of cutting is taken from the actively growing, soft tip of a stem and roots most quickly but wilts most easily?

Answer: Softwood cutting

Softwood cuttings taken from new, non-lignified stem tips root rapidly because cells are actively dividing, but require high humidity to prevent wilting before roots form.

Rain sensors on irrigation systems are required by law in some US states because they:

Answer: Automatically override irrigation during and after sufficient rainfall

Rain sensors interrupt irrigation cycles during or after adequate rainfall events, preventing wasteful over-irrigation and reducing stormwater runoff, which some states mandate.