There are no (well, maybe a few) rules to designing an outdoor space, but it helps to select a style to use as a model of sorts. This strategy helps narrow the choices when there are seemingly endless options for plants, rocks, mulch, water features, etc. Here are several examples of tried-and-true garden styles.
The English Garden
This frequently-heard term can be confusing, really. It can mean one of two things which are polar opposites. One is the formal garden, the other the cottage garden, both discussed below.
The Formal Garden
This is the traditional style of European estates, think The Palace of Versailles. Shrubs and perennials are used as a permanent elements that complement the architecture of your home. These manicured plants create symmetrical patterns, straight lines and precise geometric shapes. You will often see topiaries and wrought iron garden elements. This landscaping style requires a lot of maintenance.
The Cottage Garden
This informal style is generally found in smaller properties and creates a homey atmosphere. You will see plant beds with curved edges, with plants in seemingly random patterns. Flowers bloom throughout the year. The beds are densely planted and may include edible plants. Generally the beds are wide, allowing for several heights of plants for a lush fullness. These gardens may be surrounded by a fence to enclose the space, and cllimbing vines are often used to cover arbors.
The Asian (or Zen) Garden
This term is also misleading because it can mean several things. When used here, it generally refers to a Chinese garden or a Japanese (Zen) garden. Both incorporate water, rocks and evergreens with a variety of plants to create a tranquil environment. All five senses are engaged in these thoughtful landscapes, with sounds and smells intentionally incorporated. The difference between the two styles is that the Chinese garden uses vibrant colors, while the Zen garden uses non-flowering species and calming, muted colors.
The Woodland Landscape
This style uses evergreens and rocks to mimic the flora of the surrounding area. This style is primarily used in Northern climates, usually in rural and semi-rural locals, where the landscape has plenty of naturally derived water sources.
Butterflies, birds, and bees make a garden worthy of watching. Certain species of plants provide a food source and are useful for attracting these flying friends. Incorporate a water source like a birdbath will ensure your new friends stay in your yard. Adding a solar pump will attract the birds' attention, letting them know where the water is.
Especially popular in dessert climates where water is scarce, this landscape includes low-water plants and flowers, as well as design elements that reduce water evaporation. A design might include an area to capture rainwater when it does come, either in storage tanks or to the groundwater beneath the surface. Trees are often incorporated to provide the sorely needed shade.
Organic vs. Chemicals
Whether you grow your own food or just some shrubs, it is important to avoid chemical fertilizers and treatments. Residual chemicals can stay in soil for years and often negatively impact the ecosystem in your yard. No matter the style you choose, I recommend always using organic products in your landscape.
Of course this only scratches the surface of the subject; I encourage you to delve a little deeper into the styles that spark your interest.