I take partial blame for this problem and other writers should too: Oversimplification to the point of misinformation. We try so hard to make everything we write as easy to understand as possible that sometimes we leave out so much detail that what the reader sees is no longer completely true. One of the most common examples of this that I see is in articles and instructions on how to care for plants.
From so many of these things, you might get the impression that almost all plants can be cared for the same way. This is patently untrue! Green, flowering plants (which are mostly what we talk about) are one of the most diverse groups of living things on the planet. Each genera (or closely related group) of plants has different requirements to thrive and different adaptations to help them survive less than ideal conditions. Plant care that would make an agave thrive would kill an aloe plant and vice-versa for exa
One of the biggest mistakes we make is in assuming that we can care for plants in broad categories with a slightly different cookie cutter approach for each category. Grass is a prime example. There are far too many examples out there of advice on how to care for your lawn that might work (or might not, depending on where you live but that's yet another subject) for one genera of grass but might kill grass in another genera, yet some of these pieces of advice are portrayed as being applicable to all turf grasses. Some people think that all grass is just like Bermuda grass, for example and treat it that way.
This Bermuda grass is colonizing a patch of previously bare soil where an outdoor playhouse used to be. It got a jump start from me using a technique called 'sprigging'. This picture was taken two years ago. Now, you can't tell where the bare spot was at all.
Actually, Bermuda grass is something of a freak of nature and is very different from most other commonly used turf grasses. It thrives on abuse. It reproduces by seed, stolon (above ground horizontal stems) and rhizomes (below ground horizontal stems). When you break these stolons and rhizomes during mowing, pulling etc. it actually stimulates the plant to grow even more of them. Abuse also stimulates the plant to produce more flowers (those 'turkey foot' looking things that it grows). The growing points in Bermuda grass are not only in the base of the plant, but in these horizontal stems which can grow new roots and tillers (or upright stems) at almost any point along them if conditions are right. This grass is adapted to living in harsh, full sunlight and even salty environments such as along the coast of an island as the name Bermuda might suggest. About the only way to kill it once it's established is with several months of below freezing temperatures coupled with 100% shade. If those difficulties aren't around, nothing else will hurt it. There aren't any herbicides available to the general public that will kill it no matter what the label says. Even most of the professional stuff only stunts it for a short time. It is so able to go into a dormant state that as soon as you quit spraying for it, it will come right back.
I've even seen people spray it, stop watering it, mow it right down to the ground, cover it with a layer of 'weed barrier' (which is worthless, don't buy it!) and crushed rock out here in Vegas. As long as it is kept dry, it seems to be dead. But it is only sleeping. As soon as you plant something else you want such as a flowering yucca or agave or cassia etc. in this 'xeroscape' landscape you've created and start watering it, you'll start having little green, leafy stolons popping up. If you don't pull them or spray them on a regular basis, you'll soon have a nice little patch of Bermuda grass turf around your desired plant. I've even seen the stolons climb up through the branches of a shrub like it was a vine or something. If you want this for a yard, these traits make for a nearly fool proof turf. If you don't want it around, they make for something that is pretty much a noxious weed as far as you are concerned. The picture above is a good example of this situation. It will take some time to get this allegedly 'dead' Bermudagrass under control.
And then you have the other commonly used turf grasses. These, such as Tall Fescue, Italian Ryegrass, Kentucky Bluegrass and such will barely survive in the Southwest without plenty of irrigation and care. Many of them, such as the Fescues and Ryegrasses, are bunch-grasses and have only a few growing points in the base of each bunch. When the grass starts to grow flowers (botanists call them 'inflorescences of florets' when it comes to grasses), these growing points are elevated up towards the middle of the stems. If these stems get whacked off below that point, that stem won't grow anymore. Even the other sod-grasses like Kentucky Bluegrass, aren't as aggressive as Bermuda since, while they might have rhizomes, they don't have the ability to stay dormant for such long periods and the rhizomes aren't quite as able to punch through soil that seems to be too hard and dry for plant life.
These grasses are not nearly as tough as Bermuda and are killed quite easily. Giving them too much water is just as deadly to them as not enough water as their roots drown much more easily than Bermuda's do. They need partial shade for at least part of the day in our climate, but can't handle anything near 100% shade. In full sun, they need irrigated a lot to avoid burning up (although it's a myth that replacing turf-grass with trees and shrubs saves water since trees and shrubs use more water than most people realize, more on that in another article). If you mow off more than the top 1/3 of most of these grasses on a regular basis, you will eventually kill them as they won't be able to produce enough carbohydrates to replenish their root reserves and to grow more roots. You'll wind up with grass that has shallow, weak roots that will also require more irrigation as they won't have enough roots to get to water that has soaked down deeper into the soil. You also prevent them from flowering and producing seed that can grow new plants for you, so guess what? You wind up buying more seed and spreading lots of that out in hopes that some of it survives and 'thickens' up your turf.
The result of a turf that starts dying off or 'thinning out' as some say, is an increase of 'weeds' or other plants that you don't want in your yard. Seeds from all sorts of plants fall on your yard on a regular basis, being carried in by the wind, water, stuck to feet, in pots of potted plants that you buy, etc. If a seed lands in a spot with enough water, sunlight and lack of competition, it may germinate and grow a new plant. What happens then? People spend even more money to spray and/or pull those 'weeds'. If they apply the herbicide incorrectly, they may even wind up weakening the very grass they are trying to keep.
Oleanders are the shrub above while the groundcover below is Lantana. This is one of the lavender varieties which spread wide rather than forming a small bush as the red and yellow varieties do.
Another major example of treating all plants the same centers around the ubiquitous ornamental shrub of the Southwest: the Oleander. I like Oleanders! They can be quite nice when used correctly as the picture above shows. They are nearly as foolproof as Bermuda grass. They need very little water too. You can see evidence of this by looking at all of the abandoned and neglected lots in towns in the Southwest. The last shrubs to die when the irrigation is shut off for good are the Oleanders. In fact, sometimes they thrive even more now that most of the competition is dead and no one is pruning them anymore either. If you want a nearly foolproof plant for shade, blocking the wind and giving you fragrant flowers, it's a good choice. If you want a more 'native and natural' look for your Southwest landscape, they'll be as big of a weed as the Bermuda grass :) Oleanders tolerate excessive and abysmally poor pruning jobs better than any other shrub I've ever seen. You can hack at them all you like and they'll survive. I've even seen people cut an established Oleander clear to the ground only to have it grow new shoots around the cut off trunk. In a couple of years, they've got a little Oleander shrub right back where the stump used to be visible. About the only way to kill them, it seems, is to dig the stump up. Even then, you'll have seeds from the pods those pretty flowers produce germinating for years.
And.......Then you have the other shrubs we want to grow. Most of them, like Feathery Cassia, Purple Cloud, Rosemary, Acacia, Mesquite etc. (yes, Acacias and Mesquites are Shrubs not trees, more on that in another post). These plants have different requirements and abilities from each other as I mentioned above. They do have one thing in common though: none of them are as tough as Oleanders! We've simply got to stop treating them like they are. They cannot survive being pruned too frequently, too closely to the trunk and main branches, having too many leaves removed, at the wrong times of the year etc. like Oleanders can. They also need more water, even the 'desert adapted' ones. They simply don't grow as rapidly nor quickly develop as massive of a root system as Oleanders. If you want to have healthy, thriving shrubs other than Oleanders, you need to do your homework about the specific species of shrub that you want and do your best to meet it's specific needs. Same goes for turf grasses, ornamental grasses and flowers (yes, not all flowers can be abused like Lantanas can either).
We highly recommend obtaining the services of experienced, knowledgeable people like ourselves who are here to help you succeed, not just to sell you products and wait for you to come back for replacements. Whether you want to do as much gardening as you can yourself or are looking for someone to take care of your garden for you, it's really important to get advice and assistance from people who can tell their Bermuda from their Tall Fescue and more importantly, know how to properly handle each one.