Louise Roesser earned her BS in ornamental horticulture from Virginia Tech and is the horticulture instructor with Portsmouth Public Schools in Portsmouth, Virginia.

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Find Out Your Garden I.Q. Quiz
by Louise Roesser    

Are you a garden expert, a weekend gardener or just a novice? Challenge your gardening knowledge by taking this short quiz — you may be surprised to see where you rank. Answers are posted at the end. Good luck!

Can you identify the following plant material?

1. This is what small tree used as a specimen plant in this landscape?
  • Flowering Dogwood (Cornus florida)
  • Eastern redbud tree (Cercis canadensis)
  • Tulip magnolia (Magnolia liliiflora)
2. This is the flower of what common houseplant?
  • Wax Plant (Hoya carnosa)
  • Lantana (Lantana montevidensis)
  • Leek (Allium ampeloprasum)
3. This is what large evergreen shrub or small tree?
  • Bay (Laurus nobilis)
  • Ligustrum (Ligustrum sp.)
  • Anise (Illicium sp.)
4. This is the flower of what herbaceous perennial?
  • Cabbage rose (Rosa × centifolia)
  • Azalea (Rhododendron roseum)
  • Tree peony (Paeonia suffruticosa)
5. This is a must for your garden. What is it?
  • Woodland Phlox (Phlox divaricata)
  • Alpine Aster (Aster alpinus)
  • 'Purple Robe' cup flower (Nierembergia caerulea)

Can you identify the following insect damage?

6. You may find this unique-looking caterpillar devouring your parsley. Can you identify it?
  • Peacock butterfly larvae
  • Black swallowtail butterfly larvae
  • Monarch butterful larvae
7. What could cause all this damage to your junipers?
  • Bagworms
  • Soda imbalance
  • Overwatering
8. This pest can turn a Hollywood juniper into an unsightly mess.
  • Aphids
  • Spider mites
  • Mealybugs

Can you identify the following diseases that caused these symptoms?

9. This disease is becoming a big problem on petunias in the South.
  • Late blight
  • Erwinia tracheiphila infection
  • Crown rot
10. You may notice these on your azaleas when the nights are cool.
  • Ice formations
  • Leaf gall
  • Azalea fruit
11. Can you explain what caused the red spots on these leaves?
  • Entomosporium leaf spot
  • Paint splatter
  • Human to plant measles crossover

Test your general knowledge

12. Is an Irish potato a swollen stem or root?
  • Stem
  • Root
  • None of the above
13. If you start a new plant from a cutting, where are the roots typically produced on the cutting?
  • Middle of stem
  • At the soil line
  • The leaf nodes
14. Apples and pears are produced on short, stubby side stems called this name?
  • Stilettos
  • Spurs
  • Wedges
15. Is iron (Fe) considered a macronutrient or a micronutrient?
  • Micronutrient
  • Macronutrient
  • Iron is not a nutrient
16. The bottom, older leaves of your plant are turning yellow. Is this an indication of a zinc deficiency or a nitrogen deficiency?
  • Salt deficiency
  • Zinc deficiency
  • Nitrogen deficiency
17. Which two colors of the light spectrum have the greatest effect on plant growth?
  • Blue and red
  • Yellow and green
  • Orange and red
18. At what temperature does a compost pile need to reach in order to kill most weed seeds and harmful organisms?
  • 212° F
  • 160° F
  • 101° F
19. Is the green lacewing considered a pest or a beneficial insect?
  • Beneficial insect
  • Pest
  • Not an extant species
20. Does the term pesticide only refer to a product that controls insects?
  • The term "pesticide" should never be used
  • Yes, it is specific to insect control
  • No, it's a broad category
21. Where is the best place to store seeds after purchasing and opening them?
  • In the ground
  • Sealed plastic bag in a refrigerator
  • Closed container of liquid fertilizer
22. Branch angles of less than X degrees from the main trunk result in a very high percentage of breakage.
  • 30 degrees
  • 90 degrees
  • 15 degrees
23. When performing gradual rejuvenation on a deciduous shrub, how much of the shrub's growth should be removed the first year?
  • All, cut to the ground
  • One-third of oldest branches
  • None, do not prune
24. What is the best way to keep soluble salts from building up in the soil of your indoor plants?
  • Allow some water to drain through pot openings
  • Add a small amount of table salt each month to acclimate plants
  • Grow all plants hydroponically
25. When potting an amaryllis bulb, how much space should you allow between the bulb and the edge of the pot?
  • 2-3 inches
  • 0.5-1 inch
  • 4+ inches
26. When planning your vegetable garden always locate the taller vegetables on the _____ side of the garden.
  • North
  • West
  • East
27. How often should you have your vegetable garden soil tested?
  • Every year
  • Soil tests are a waste of time
  • Every 3 years
28. How many different varieties of apples should be planted for adequate cross-pollination?
  • 3+
  • You only need one
  • 5+
29. When is the best time of day to water your lawn?
  • Midnight
  • Early morning
  • Noon
30. How long should supports of newly planted trees be left in place?
  • One year
  • Two years
  • Landscaping trees need to be supported indefinitely


Get Your Score
Now it's time to find out how much you know. Click "Get score" to find out. Be sure to see the detailed answers below.

Let us know how you did by leaving a comment at the bottom of the page.

Score =

Your're germinating.
Your're sprouting.
Your're a seedling.
Your're well rooted.



1. This is an Eastern redbud tree (Cercis canadensis). It features heart-shaped green foliage with deep purple-pink flowers in early spring. Zone 4.

2. This is the flower of a wax plant (Hoya carnosa). This plant makes an excellent hanging basket for your home with little care.

3. This large evergreen shrub is known as anise (Illicium sp.) which prefers a moist, shady location. The leaves contain aromatic oils. Zones 4 to 7.

4. This is the flower of a tree peony (Paeonia suffruticosa), a medium-sized, spreading deciduous shrub with exceptionally large flowers in the spring. Zones 4 to 9.

5. This is 'Purple Robe' cup flower (Nierembergia caerulea), an annual in parts of the south, but hardy in Zones 10 to 11. This plant features fine-textured foliage and bright blue flowers from late spring through fall.

6. This pest is one you can tolerate in your garden because it is the larvae of the beautiful black swallowtail butterfly. Just plant extra parsley for the parsley worm.

7. This pest, the bagworm, can cause extensive damage to junipers, arborvitae, cedar, and other evergreens. Pick off and destroy "bags". Spray with Bt (Bacillus thuringiensis) between May and mid-July.

8. When weather turns hot and dry, be on the look-out for spider mites which caused this discoloration.

9. This is crown rot on a petunia caused by Phytophthora nicotianae.

10. Azalea gall or leaf gall is a common spring disease of azaleas, rhododendrons, and camellias. Hand remove and discard galls or plant resistant varieties.

11. The red spots on this Indian hawthorn are caused by Entomosporium leaf spot. Avoid wetting foliage, especially late in the day.

12. An Irish potato is an enlarged portion of an underground stem. The eyes of a potato are actually the nodes on the stem. Each eye contains a cluster of buds.

13. At the nodes or areas where leaves and buds are attached.

14. Spurs.

15. Iron is essential to enzyme functions but is only needed in small amounts, so it is considered a micronutrient.

16. A nitrogen deficiency.

17. Blue light promotes leaf growth and red light combined with blue light encourages flowering in plants.

18. 160 F.

19. The green lacewing is considered a beneficial insect. Both larvae and winged adults eat large numbers of aphids, mealy bugs, cottony cushion scales, and other insect pests.

20. No. A pesticide is a broad category that includes fungicides, herbicides (weed killer), insecticides, and others.

21. Seeds should be stored in a sealed plastic bag and placed in a refrigerator.

22. 30 degrees

23. One-third of the oldest, unproductive branches should be removed during the first year.

24. When you water, allow some to drain through the pot openings to leach salts from the soil.

25. One-half to 1 inch when planted on center.

26. The north side so the taller vegetables won't shade the shorter ones.

27. Your soil should be tested at least once every three years.

28. At least three varieties.

29. Early morning when evaporation is minimized and the potential for disease activity is less.

30. All supports should be removed within one year after planting. It has been reported that growth is actually reduced if supports are left in place after one year.


(From State-by-State Gardening March 2005. Identification photos by Louise Roesser.)


Posted: 02/29/12   RSS | Print


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Christopher (Louisiana - Zone 8a) - 03/01/2012

Fun quiz! I’m “Well Rooted.” Barely made it in with 83%.

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Jess Moore - 03/02/2012

I’m a seedling (60%), but I’m germinating. : )

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Rick (Indianapolis, Indiana) - 03/07/2012

Guess I better brush up on my insects and plant diseases. 80%..

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