If you're just starting out gardening or taking over a new plot and worried you don't have green fingers, here's a tip that will save you a lot of wasted effort and money: Choosing the right plants to grow in a garden will vastly improve your success rate. To make life even easier, here's how to choose plants that will thrive in your garden.
Climate and hardiness zones
There is no point planting something that won't survive in your local climate. The U.S. Department of Agriculture provides a map of North America, showing the hardiness zones for plants. Check the map to learn your local hardiness zone, and make sure the plants you choose are suited to it.
Your garden and microclimates
Even in a small garden, you will have microclimates in some areas. Get to know your garden. Know which areas receive full sun (more than six hours a day), which are in partial shade (two to six hours of sun) and which provide full shade (fewer than two hours of sun.) Draw a map of your garden, and mark these areas on it.
Look at the soil in your garden. Are some areas damper than others? Do you have richer soil in one section? Is another harder to work, with heavier clay or loose loam? Mark that down, too. Check the soil pH (acid or alkaline balance) in each of these areas, and note that on your map. Also make note of any sun traps, where the heat of the sun is amplified by surrounding walls, and wind tunnels, where plants would be exposed to through winds.
Now that you know what type of garden you have, choosing plants to grow in it becomes much easier. The Saving Water Partnership has two excellent resources, Choosing the Right Plants and The Plant List, to help with this in the Northwest.
Choosing the best plants
You probably want to see a quick result if you're dealing with a new garden, in which case choosing annuals that will thrive in your conditions will give you almost instant rewards. Thinking long-term, though, it's best to start with the architectural plants that will shape your garden over time. These are the trees and shrubs, the tall grasses and large perennials.
As a general rule, place the tallest and slowest-growing plants first, and take into account the space they will need when they are mature. You can always plant annuals or short-lived perennials in the space they will grow into until they need it. Just be careful not to crowd them out or force them to fight for nutrients.
Once you have your architectural plants in place, consider if they will change the microclimate in bordering beds by adding shade or depriving the soil of nutrients, and adapt your planting to allow for this. Choose smaller perennials that make good companion plants. Unless you want to leave annuals to self-set year on year, it's best to group them together in a single border.
When you visit the nursery to choose your plants, choose shorter, bushy plants over taller, spindly ones, and go for those showing lush, green growth. Check the soil and leaves for signs of insect infestation or disease, and always check the root-ball. If the roots are growing out of the pot, or curling in circles around its bottom, the plant is pot-bound and may struggle to adapt to a new setting.
Knowing your garden and it's individual characteristics, and choosing the healthiest varieties of plants suited to those conditions, will give you the best possible chance of growing healthy plants that you can enjoy for years to come.