It is very gratifying to go out to the nursery, etc. filled with enthusiasm that you are looking to plant drought tolerant species for your garden. One very important thing to remember is that your plants have been grown under nursery conditions and they are small and young plants. This is important because although they will tolerate dryness, they first need regular watering in order to become established in your garden. This time frame to establish deeper roots which provide drought tolerance can take anywhere from 1-5 years. Some small growing species like native bunch grasses can establish rather quickly, while trees and shrubs will take longer. An important detail is also how much regular watering the species will tolerate as it becomes established.
With all containerized material, you should plant slightly higher than grade since the soil will settle from the planting installation. If the root ball settles higher than grade, you can make up the difference by adding mulch. Thorough watering is key and deep watering will help get roots to lower soil levels. Then let the plant dry out slightly. You want to provide intervals where the plant stays hydrated and also have the soil dry out enough to allow air to return to the soil structure for good root growth.
You can plant from conatiners anytime. Fall is often recommended, but when in containers, plants are established in the pots, and will be anxiously awaiting in ground planting, any season. You will get much root growth in the fall and winter seasons when it is cooler and also wetter, but remember that the sooner you place the plant into the ground, the sooner it will start growting and get established in your garden.
If planting in hot weather, gently tease the roots of most plants if they are circling in the container. If you are planting many, then just make shallow vertical cuts into the root ball from top to bottom of the root ball and then underscore with an ‘X’ the bottom of the root ball.
Some nice species:
Arctostaphylos (the manzanitas) many from which to choose: ground cover carpets to mounding shrubs, larger shrubs to almost small tree like.
Ceanothus: (California lilac): a large group as well, these need excellent drainage. They are not extremely long lived plants under gardening culture with regular watering (on mature plants). Young plants can tolerate more watering than old established plants. ground cover, many intermediate shrub forms, and on up to small tree size, flowers in blues, white, rarely pink. For a nautral soap, wet hands in water, then grab a cluster of blossoms and rub vigorously to make a soap from the wet blossoms and they have a nice fragrance too.
Romney coulteri (matilija poppy) a subshrub, tall perennial poppy with crepe paper white petals and yellow boss of stamens on large poppy flowers. Fragrant as well. Fully open blooms look like fried eggs. Do NOT disturb the roots if at all possible since poppies resent root disturbance. Regular watering will promote longer blooming, but they are quite drought tolerant after the first year.
Lobellia laxiflora: one of the almost continuously blooming clumping perennials for full jot sun. They bloom in open clusters atop many stems in the clump. Narrow foliage, and clusters of red tubed range yellow petals. In bloom almost continuously. A great hummingbird plant. Very tough and drought tolerant. full sun.
These make formidable barriers since the leaves are hook spined. They are sharp all over, and picturesque in outline of clustered clumps of foliage. Spectacular bloom stalks arise and bear trumpet funnel shaped blooms in satin finished colors of metallic blues, and greens. Full sun, these form large impemetrable clumps which are showy in bloom. If you want a barrier planting and want to preserve a view, try this!