Most of my clients ask for a low maintenance garden. Unless they have unlimited resources, most of my clients would prefer to keep their ongoing maintenance costs to a minimum. The initial maintenance of getting a garden established is very basic, provide enough water for the new plants to thrive, don't over water and keep weeds from getting a foothold. The amount of long term maintenance is really a function of design choices. If you have a turf area you will have higher ongoing costs for watering, fertilizing, herbicides, pesticides and mowing than a garden that has little or no turf. But just because a garden has no turf does not mean it is low maintenance, in fact it could require more maintenance than turf. A classic garden of clipped hedges and topiary requires constant maintenance to retain it's form, that is a consequence of design choice. The ultimate expression of this would be the miles long clipped al-lee at Versailles in France. When a tree becomes to large to continue pruning it is cut down and a new one is planted in it's place.
A traditional Japanese Garden also requires considerable maintenance in order to achieve and keep a certain look. As these are highly stylized interpretations of nature, the plant material is not allowed to reach full size but is kept at what is desired to be the correct size. Bonsai is the ultimate expression of this, but even the trees growing in the garden are almost a larger version of Bonsai. This is a design choice.
Paving choices influence maintenance costs. A brick on sand patio will eventually suffer from underlying erosion and sink here and there. As the brick settles and the spaces between open up, weeds can get a foothold and speed up the process. I usually design a brick patio, or flagstone patio to have a concrete pad underneath, to mortar the brick and have a grout joint. This will last much longer. If the patio is going to affect the rooting area of an existing tree, not usually the best place for a patio, pavers on a compacted base will have less affect on the tree and can be reset if they are displaced by tree roots. A decomposed Granite walkway or patio may hold up extremely well in the dry desert southwest, but in much of Northern California we get enough rain that weeds will grow on it and it will erode when water runs across it. I usually have a stabilizer added to it, which works well, but is allot more expensive. Again, these are design choices.
The choice of irrigation systems and drainage systems also affect maintenance. A sprinkler system is simple and easy to see if there are problems. However, many people ignore problems with their sprinklers until it's painfully obvious. In the meantime, some areas have been getting too much water, some not enough, plants are dying, weeds are growing from all the watering and run-off is a major issue. A drip system has it's limitations as well, but it doesn't have the under/over watering issues, doesn't grow weeds and doesn't waste water. If grading and drainage aren't properly installed they can create wet areas during the both the growing season and the winter time. This can kill plant material and grow weeds.
Mulches can lower maintenance by limiting (not eliminating) weed growth, provided they are at least 2" thick and promoting better plant health by improving the quality of the soil as they break down.
All of this being said, I think the number one design choice that creates high maintenance is plant material. Planting a plant that will easily grow 20 ft. X 20 ft. in a 3ft. X 3ft. space is a recipe for high maintenance. I see this all of the time, people have to constantly prune plants to keep them from taking over their garden and most of the time there are many plants in the same garden that are too big for the space. it could be the choices made by the developer, they often choose large plants for that immediate look, but aren't doing anyone any favors. Or it could be what was on sale at the nursery or department store, or what a landscaper chose to plant, just because they call themselves a landscaper doesn't mean they know anything about plant material.
If you want low maintenance in your garden, and most of my clients aren't gardeners, they are paying someone else to do the maintenance, you have to understand plant material and choose appropriately. This is much easier now than it was a mere fifteen years ago, today there are countless plant varieties that have been grown specifically for their dwarf size. It requires a greater number of these smaller plants to fill the space, but it results in much lower maintenance.
If you want a low maintenance garden make the right paving choices, grade correctly, install proper drainage, a drip system, mulch, no turf and above all think small when it comes to the plant material choices.
