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Applied Quiz: Garden Design with Native Plants

A second set of questions on this chapter, weighted toward using the ideas rather than recalling them. Each one puts you in a situation and asks what the chapter's framework says to do.

1. It is the second summer after your native planting went in. The bed still shows bare soil and half the forbs have not bloomed. Your neighbor says it failed. What does this chapter say?

  1. He's right — a healthy planting fills in by year two
  2. Year 2 is the hardest year and looks exactly like this; natives build root systems before topgrowth, drifts knit together in year 3, and the planting matures around year 5
  3. The plants were spaced too closely
  4. The site needs fertilizer to speed things up
Show Answer

The correct answer is B. The chapter's year-by-year table exists to answer precisely this worry, and Bree's admonition names year 2 as the discouraging one. A Baptisia can spend its first summer building a two-foot taproot with very little to show above ground. The advice is to resist digging things up.

Concept Tested: How a Native Garden Develops Over Time

See: Chapter 10

2. You dig a 12-inch hole, fill it with water twice, and the second fill drains in about six hours. What does that tell you and what should you plant?

  1. Fast drainage — plant dry prairie species
  2. Slow drainage, a wet site — plant species that tolerate saturation, such as Blue Flag Iris, sedges, or Joe-Pye Weed
  3. The test is invalid; percolation tests need 24 hours
  4. Moderate drainage — plant anything
Show Answer

The correct answer is B. The chapter's percolation thresholds are under 1 hour for dry, 1 to 4 hours for mesic, and more than 4 hours for wet. Six hours puts you clearly in the wet category, and as the chapter says, this simple test tells you more than any plant label.

Concept Tested: The Percolation Test

See: Chapter 10

3. You assess sun exposure in late March and record 7 hours of direct sun under a big maple. Why might that reading mislead you?

  1. It won't — sun exposure is constant year-round
  2. Deciduous trees have not leafed out in March; the chapter says to measure on a midsummer day, because that same spot may be deeply shaded by June
  3. March sun is too weak to count
  4. You should measure in winter instead
Show Answer

The correct answer is B. The chapter specifies late June or July for a reason. It also notes the flip side: that spring window of light under a deciduous canopy is exactly what woodland ephemerals like Bloodroot and Virginia Bluebells depend on — so the March reading is meaningful, just not for choosing summer perennials.

Concept Tested: Measuring Sun Exposure

See: Chapter 10

4. A gardener spaces native perennials 3 feet apart "so they have room to grow," the way she would in a perennial border. What does this chapter say happens?

  1. The plants will be healthier with extra room
  2. This is the common beginner mistake — native landscapes in the wild are dense, and wide spacing leaves open ground that weeds colonize instead
  3. The plants will die from lack of competition
  4. Spacing has no effect on weed pressure
Show Answer

The correct answer is B. The chapter's guidance is 18 to 24 inches for tall perennials and 12 to 18 for medium ones, with the goal that plants grow into one another. Density is a weed-control strategy, not just an aesthetic one — bare soil in a native planting is an invitation.

Concept Tested: Plant Spacing and Density

See: Chapter 10

5. A jar test on your soil settles into a thin bottom layer and a thick top layer after 48 hours. What do you have, and which of these plant sets fits?

  1. Sandy soil — plant Butterfly Milkweed and Little Bluestem
  2. Heavy clay — and rather than fighting it, plant clay-tolerant natives like Wild Bergamot, Joe-Pye Weed and New England Aster
  3. Loam — plant anything
  4. The test failed and should be repeated
Show Answer

The correct answer is B. Sand settles first at the bottom and clay last at the top, so a thick top layer means clay-heavy soil. The chapter's point is that this is a plant-selection input, not a problem to correct — plenty of Minnesota natives prefer clay.

Concept Tested: The Jar Test and Soil Texture

See: Chapter 10

6. Someone plants Blue Flag Iris on the rim of their rain garden and Little Bluestem in the center. What will happen?

  1. Both will thrive; rain gardens are uniformly moist
  2. Both are likely to struggle — the zones are reversed. Blue Flag Iris belongs in Zone 1 at the wet center and Little Bluestem on the dry Zone 3 rim
  3. Only the iris will fail
  4. The design is fine as long as the garden drains within 48 hours
Show Answer

The correct answer is B. A rain garden is three distinct habitats in one small feature, which is what makes zone assignment the core design decision. Little Bluestem is a dry-site prairie grass and will rot in standing water; the iris will dry out on the rim.

Concept Tested: Rain Garden Planting Zones

See: Chapter 10

7. A homeowner wants a rain garden and proposes putting it 4 feet from the house foundation in the lowest spot in the yard. What does the chapter say?

  1. Ideal — the lowest spot collects the most water
  2. Move it: rain gardens belong at least 10 feet from a foundation, positioned downslope from a downspout or driveway, with an overflow outlet directing extreme storms away from buildings
  3. Distance from the house does not matter if the soil drains well
  4. Rain gardens should be built against the foundation to catch roof runoff
Show Answer

The correct answer is B. The 10-foot setback is about not deliberately infiltrating water next to a basement wall. The overflow outlet matters for the same reason — the design has to handle the storm that exceeds its capacity, not just the average one.

Concept Tested: Rain Garden Siting

See: Chapter 10

8. A landscape architect needs to move stormwater across a long side yard, not just hold it in one spot. Which does this chapter point to, and how does it differ?

  1. A rain garden, since both features handle stormwater identically
  2. A vegetated bioswale — a shallow planted channel that conveys water while slowing and filtering it, as opposed to a rain garden's basin that holds it
  3. A french drain with gravel
  4. A retention pond
Show Answer

The correct answer is B. The chapter draws this distinction explicitly: capture-and-hold versus convey-and-slow. They also use different plant palettes — the bioswale leans on sedges and rushes whose fibrous root mats armor a channel against moving water.

Concept Tested: Bioswales vs. Rain Gardens

See: Chapter 10

9. In year 5, some of the Wild Lupine in a planting has died out while other species have self-seeded into the gaps. Is something wrong?

  1. Yes — species loss means the design failed
  2. No — the chapter says this is expected by year 5; lupines often drop out, and the composition succeeding rather than staying fixed is the sign of a maturing planting
  3. Yes — the self-seeders are almost certainly weeds
  4. No, but the lupine should be replaced every year
Show Answer

The correct answer is B. The chapter's year-5 row names lupine specifically as a species that often dies out as expected. A native planting is a community in motion, and by year 10 the job shifts to gentle editing rather than maintaining a fixed plan.

Concept Tested: Long-Term Garden Succession

See: Chapter 10

10. A homeowner sizes a rain garden at 20 square feet to catch runoff from a 600-square-foot roof section. What does this chapter's guidance suggest?

  1. That's about right — small rain gardens are more effective
  2. Far too small; the guideline is roughly 20 to 30 percent of the impervious area draining into it, so 600 square feet of roof calls for something in the 120 to 180 square-foot range
  3. Rain garden size does not depend on the drainage area
  4. It should equal the full 600 square feet
Show Answer

The correct answer is B. The chapter gives both the percentage rule and a typical residential range of 100 to 300 square feet. An undersized basin simply overflows in ordinary storms, which defeats the infiltration the garden exists to provide.

Concept Tested: Sizing a Rain Garden

See: Chapter 10