Not sure what type of soil you have, but there’s a good chance it’s hard pack clay with a ton of rocks in it. If this is the case you will end up with a lot of displaced clay soil and rocks that need to be hauled off the property. This is because most experts recommend digging a hole that’s 2-3 times wider than the pot that the plant came and the amending the clay with around 30% planting soil. You have to get rid of the clay displaced by the new plant, and the 30% of the clay that was replaced by the planting soil. I would also get rid of any rocks that are bigger than a golf ball. If you go the DYI route, your best bet would be to order a truck load of bulk planting soil and have it dumped in your driveway, since buying it by the bag is very expensive.
When you are done planting it’s a good idea to cover any exposed soil with 2-3” of mulch. This will vastly improve the water retention of the soil, inhibit weed growth, and will look great. The most common type of mulch is Redwood bark chips or shredded Redwood bark (aka Gorilla Hair). Bark chips do not work well on steeper slopes since that can slip down when walked on or wash away in a heavy rain storm.
Regarding irrigation; drip systems are the most efficient way water, but they are time consuming to install, and a huge pain to maintain. Over time, the drippers (aka emitters) often get plugged up, or pop off. Surface roots and foot traffic aggravate this problem. Often you don’t notice this until the plant dies. When a dripper pops off the water spews out at full pressure. If even one dripper pops off (and goes unnoticed) any water savings inherent to a drip system are more than lost. It’s really easy for a bad dripper to go unnoticed since they are usually covered by mulch or the plant itself. Even if they are clearly visible you have to get really close to see whether they are working or not. If you do use drippers ensure that the pipe feeding them has a pressure reducer installed (unless you have really low water pressure) and the drips themselves are the pressure compensated type. If you can do all your watering with pop-up sprinklers it’s a lot easier to maintain, but in theory (not necessarily in practice) less water efficient. The problem with sprinklers is run-off and evaporation. If the system is setup right run-off is minimal and evaporation can be greatly reduced. Run-off can be reduced by running the system in multiple intervals. For example, instead of setting the timer to come on for 9 minutes, set it to run 3 times for 3 minutes with a half hour in between each interval. This gives the ground a chance to absorb the water. Evaporation can be greatly reduced by running the sprinklers a few of hours before dawn. The biggest problem with using sprinklers is that different species of plants have different water requirements. You can’t meter the water delivery to each plant like you can with a drip system. However, if you use plants with similar water requirements this is not a problem. Also, some plants (not many) do not like to their leaves and branches to get wet on a regular basis. Sprinklers tend to be much more reliable than drips, but when they do fail it’s far easier to visually detect it.
I would recommend having the irrigation system installed by a professional unless you have a lot of time to do the research and the install. It’s worth it to use top of the line parts since you need the system to last forever and it will be used constantly.
If you want a low maintenance garden do not plant any fast growing vines or hedges as they will need to be trimmed constantly. If you want color in the garden the easiest thing to do is use plant with different colored foliage, since most flowers have to be deadheaded (very time consuming) if you want them to bloom more than once.
Try to determine if the property has any drainage issues as these will have to be addressed before the plants and grass go in.
Regarding grass; use a lot of top soil (at least 4” when packed) as the grass will love it and your watering bills will be much less. A lot of builders will put only 1” of packed top soil on top of hard-pan clay. The water and roots have a very hard time penetrating the rock solid clay. This results in wasted water from run-off, and weak thin grass that dries out very quickly.
I would not plant many deciduous plants since there’s a plethora of broadleaf evergreens that will grow in the San Diego climate. Deciduous plants drop a ton of leaves in the fall and are unattractive all winter. Deciduous trees do make sense if you have any spot where you want shade in the summer and light in the winter. Do not plant any trees or bushes near the pool if they are the type that drop a lot of seeds, fruit, blossoms, or leaves.
As other posters have recommended, do not allow any day labors to work unsupervised. You will need to micro manage them .Most of the staff working at nurseries are low paid and unknowledgeable. For advice go to a dedicated nursery business and seek out the owner, manager or seasoned old timer for advice. I do recommend buying your plants at a place like Home Depot (good prices with one year warranty on plants), but again, do not take any advice from them.
A good web site for researching plants is http://www.davesgarden.com. I believe they have the world’s largest online plant database. For great landscaping and plant ideas go to one of the local botanical gardens with you note pad (a lot of the plants will be labeled) and camera. I recommend shamelessly replicating landscaping that looks great, rather than trying come up with your own design, or trying to visualize a plan done up by a designer.
Finally another way to justify a DIY landscaping project is that it’s great exercise (beats going to the gym) and mentally refreshing. A wide brimmed sun hat, a stereo, and lots cold beer on hand are highly recommended.
