Are you falling for these gardening myths?

MACOMB, Ill. —  During my time as an Illinois Extension educator, I have run across many garden myths. Too many to keep track of. But some myths keep on coming up in teaching and talking with Illinoisians. Some myths are more localized, while others are widespread and often touted as garden “hacks” online.

Some garden myths have grains of truth, while others can be completely false. So, which myths are a bust? The following are some common and odd gardening myths I come across year after year.

Myth: If I treat my yard for white grubs this year, I won’t have Japanese Beetles next year.

Fact: An adult Japanese beetle can fly between 10-15 miles. When they find a suitable host plant for feeding, they release an aggregation pheromone that tells other Japanese beetles where to go for food and mating. So even if you wipe out the white grubs (which include Japanese beetle larvae) in your yard, they are more than equipped to travel from distant neighbors’ yards if you have tasty host plants.

Myth: Adding sugar to the planting hole when planting tomatoes will result in the tomatoes harvested being sweeter.

Fact: The sweetness of a tomato is pre-determined by the variety of tomato you plant. Sugar can also stimulate bacterial growth in the soil. When bacterial growth is kicked into high gear, it can pull nitrogen from the soil, which prevents your tomato plant from getting the nitrogen it needs. A better use for sugar is cake or cookies.

Myth: Ants are integral to helping peony flowers open.

Fact: That would be a neat trick, but the reality is also fascinating. Peony flower buds have small organs on the closed flowers called extrafloral nectaries. These nectaries secrete a sugary nectar that is attractive to ants. The nectary will feed the ants until the flower begins to open. This sounds like a good deal for the ants, but what does the peony get out of it? Ants will aggressively defend their food source, which in this case is the peony flower. Any other insect that comes along to take a bite out of the peony flower will have to contend with an army of defending ants.

Myth: Use salt in an asparagus patch to help control weeds.

Fact: This is somewhat true. Asparagus has deep roots and can tolerate or recover from salt damage better than shallow-rooted weeds. However, there is a reason salting your enemy’s crops was a weapon of war for hundreds of years. Using salt in an asparagus patch can eventually cause excessive salt buildup in the soil, leading to both plant damage and soil structure damage. Fortunately, salt is soluble, and over time, rainfall and irrigation can leach the salt out of the soil, but the damage will already be done to your asparagus.

Myth: Apply turf fertilizer early in the spring to help encourage new growth.

Fact: Early spring turf fertilizer encourages top growth at the expense of root growth. That root growth is necessary for your turf to survive through the summer. If you plan to fertilize your lawn in the spring, it is recommended to wait until the vigorous spring growth begins to slow in early to mid-May.

Myth: You should always amend the backfill when planting trees.

Fact: It is suggested to only add a minimal amount of amendments to the backfill in heavy clay soils. Otherwise, use the native soil to backfill the planting hole. Amending the soil can restrict outward root growth as it can be easier to grow in the amended soil, and the difference between the amended soil and the native existing soils can restrict water movement.

Myths abound in the gardening world. This is just a short list of some garden myths. If you are ever wondering about the best way to take care of your yard and garden, contact your local Illinois Extension office for help and information.