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Garden Myths Debunked: Part 2

6 min read | Dec 13, 2012 | Plants 

Myth 5Plants will grow to the size specified on the internet or in books

Plants can not read.  They do not know that humans have placed size labels on them.  Most of our plants here at the garden center have signs or labels on them that say they will get “x” feet tall and “x” feet wide.  The same goes for books and on the internet (wait……the internet can be wrong?).  Those size parameters are fine in black and white, but nature is dynamic.  A specific plant in my garden can, and most likely will behave differently than the same plant in your garden.  Different sun exposures, water availability, and soil textures play a major role in how a plant will mature.  I see this all the time.  One of my favorite examples is of a Cryptomeria ‘Globosa Nana’ that I saw inEurope.  Our literature states that this plant matures around 4 or 5 feet in height and width.  When I rounded a curve in the garden inItaly I was staring an 8’ tall ‘Globosa Nana’ in the face.  Actually, it was probably the shoulders because this shrub towered over me.  That is an extreme example but you get the point.  The size labels that we put on plants are really just guidelines.  They may stay a little smaller or grow a bit larger…..that is just nature!

Myth 6I have an irrigation system, so my new landscape is well watered

An irrigation system can be a great thing to have, but without a complete understanding of how it operates I would not trust one to water my new landscape.  Understanding an irrigation system boils down to knowing how different types of plants need to be watered and having a professional design and install the system to begin with.  If you do not have a proper system from the start, trouble will follow.  Irrigation systems should have several sets of zones.  One designated only for lawns, a set for trees and shrubs, and one for annuals.  There may be other circumstances that allow for more sets, but this is a good place to start.  A system should not water the lawn and shrub beds at the same time.  That is a waste of water and can lead to over watering of your trees and shrubs.  Trees and shrubs are more efficiently watered with a drip zone than with standard rotor heads (spraying heads that you see pop up out of the ground).  The trouble with a new landscape and drip systems can come from the placement of the drip emitters.  If the emitters are not placed directly over the root system of new plants, most of the water may not be reaching the root system.  The same goes for soaker hoses.  Observing your system while it is operating is a great thing to do every couple of weeks.  Wet or dry areas can be seen at this time and allow for adjustments to be made.  Even with a set irrigation schedule, some new plants may need supplemental water.  The most important points about irrigation systems are to have a qualified professional install the system, and thoroughly go through and explain the system to you.

Myth 7The more compost (organic matter) the better

Ok, this is a contradiction to what many plant professionals (myself included) have said for years.  First let me say that compost incorporated into our soils, particularly poor soils, is a good thing.  It is actually a great addition and helps build the soil structure over a period of time.  There is be an issue that can arise with an over use of compost……poor water retention in the soil.  In the grand scheme of soils, when compost breaks down to its smallest form, it is still a fairly large particle.  This is generally not a problem because large particles allow for great aeration and drainage.  So why is there an issue?  A couple of summers ago during our historic drought, I noticed much more plant health issues and plant death in soils that had an over use of compost.  Why…..because of great aeration and drainage.  The large particles create a ton of pore space which during a drought is obviously not holding water.  During the same drought, our native forests did not show as much plant stress and death.  Yes, the surface soils in the forest are comprised of broken down organic matter from leaves and other plant materials, but the subsoils are generally comprised of clay which has an excellent water retention capability.  The key with compost is finding a good balance with the amount of compost and your native soil.  You can reap the benefits of compost like the nutrient content and the ability to improve poor soil while utilizing the natural water retention of our native clay.  Check back to the first part of this article to read more about the positives of clay soil.

Myth 8New plant introductions are better than old plants

This is a big time pet peeve of mine.  First I will say that there have been and will be some new plants out that are fantastic.  Knockout rose has been an outstanding performer as well as the encore azaleas and many others.  The problem is that for every great new plant that is introduced, many others fail.  I think much of the blame goes to the fact that horticulture has kind of gone corporate.  In “the good old days” a new plant was trialed and observed in the landscape before its introduction to the market.  Now it seems like every major nursery is promoting their own line of new and “improved” hydrangeas, daylilies, roses, etc.  They hit the market without very little, if any trialing.  What’s worse is some of these plants (or groups of plants) are marketed across the country.  Many of these new introductions might perform beautifully in one geographic area and be a complete dog in another.  These are a few reasons why we are very selective in the new plants that we carry here at the garden center.  Sure, we get an occasional bust, but for the most part we can keep great plants in stock.  Our “old” plants have been around a while for a reason.  They are tried and true plants in the landscape.  This is just my mini-rant on new introductions.  I have many other issues for this topic but for the sake of space, I’ll keep it short.

This two part series may need a third addition.  I hope these topics will spark some conversation.  Feel free to contact us if you have any questions or would like to discuss the topics further.

Happy Planting!


Brad Rollins