SOME people say you learn more from your mistakes than you do from your successes.
When it comes to gardening, that opinion really rings true for many good gardeners.
Among the many major mistakes (no pun intended) I have made over the years, there was the walnut tree incident.
When I was first starting out I planted a black walnut tree (Juglans nigra) in a concrete planter, the walnut tree rapidly proceeded to punch its roots through the drain holes in the bottom of the planter and grow down through a crack in the patio below. The final result was a slowly bulging planter that finally disintegrated leaving a pile of soil and the bottom of the planter firmly attached to patio.
My advice: Learn your plants and understand where and how they grow before you plant a large, aggressive tree into a small planter. And listening to the advice that walnut trees are sometimes called "pavement busters" would also help.
Here's a mistake one of my friends made.
She asked me to give her some suggestions for a plant that would grow well in a boggy, wet spot adjacent to her house. After suggesting several plants, she fell in love with a picture of giant rhubarb (Gunnera manicata) that I had sent her. Gunnera is native to South America, loves moisture and grows leaves up to 3.5 metres across while producing a thick, large rhizome that sits on the surface of the soil.
It is truly a prehistoric and amazing looking plant. Only one problem: Gunnera roots will search relentlessly for water and since it was planted near the house, the roots found their way down into the house's drain tile, which became plugged.
My friend spent several hundred dollars removing the gunnera and fixing the drain tile. I did warn her not to plant it close to the house where its roots would creep their way into the drain tile, but enthusiasm overtook reason.
My advice: do not plant anything next to the house for any reason. Instead, plant away from the house. And install a half a metre wide strip of clean crushed gravel along the house to use as a maintenance strip while using the planting bed and plants to conceal the gravel strip.
Here is a brief list of other gardening mistakes to avoid:
Mistake No. 1: Fertilizing with blood meal, bone meal, alfalfa pellets or fish emulsion.
This type of hippie guru stuff is strictly for amateurs. The problem with all of those types of so-called fertilizers is the lack of accurate concentration guarantee and the source is unknown, so you could be receiving potentially useless or toxic substances with those types of fertilizers.
Mistake 2: Applying Epsom salts to enhance nutrient uptake.
This old myth rears it head every spring when rhodos and camellias develop intervienal chlorosis (yellow between the veins). The truth is that if your plants develop this problem you should test the soil pH and lime accordingly to fix the low pH problem. Raising the pH will allow the plant to access more nutrients in the soil and lime will also supply magnesium which is what Epsom salts supplies.
Mistake 3: Never till the soil deeply. It is true that healthy soil that has been properly dug, amended and mulched may never need to be re-dug. However, soil that is compacted, waterlogged, eroded, or just poor quality should be dug deeply, amended with organic matter and mulched. Deep digging does kill off some beneficial soil organisms; however, those organisms quickly re-establish in the soil, especially with the addition of organic matter which is their food. And soil must be prepared to allow new plants to fully realize their potential.
Mistake 4: Trench composting is good for the garden.
Whenever decomposition occurs, there are gases that are given off and those gases are toxic to plant roots and soil organisms. Decomposing green or vegetable waste is also attractive to rodents, like rats. So in an urban environment, trench composting is silly and problematic. Use a proper rodent-proof compost bin instead.
Mistake 5: Prune long stems by heading back to control length or height.
Heading cuts remove the end of a branch which removes hormone control which then allows all buds to grow and grow vigorously. So when you head back a stem, you actually induce bushiness and increase growth. If you want to control height, prune in summer to suppress and use a thinning cut which cuts off the end of the branch to a lower branch, thereby redirecting growth.
In the end, we all learn from our mistakes. But it takes courage to have the will to make mistakes in the first place. After all, no guts, no glory or learning.
Todd Major is a journeyman horticulturist and chief horticulture instructor at UBC Botanical Garden. For advice contact him at [email protected]
