Carefully consider the moisture conditions of the site you have chosen for your garden. Is it normal (as much as it's possible to define normal with today's chaotic weather), dry, or wet? Choose plants that do best in the prevailing conditions.
Next plan defensive measures to counteract a change in the moisture content. If the area you have chosen is dry, make sure the drainage is excellent. That way, even if there is excessive rain, the water should run off quickly. To increase drainage, dig out your garden bed to a depth of 1-1/2 to 2 feet and install a drainage pipe. This will immediately carry away any excess water. Then refill the bed with enriched, porous garden soil filled with organic matter, such as peat moss and humus.
If your proposed garden area is moist, make sure you have the means to retain the moisture. Your garden should either be near a water source where you can sprinkle the spot daily, or embedded with a soaker hose.
Or you can create your own miniature damp spot by following the techniques used to create garden pools. Simply install a container with a very small hole punched in it for slow drainage. After you've filled the container, the moisture should seep out of such a setting at a very slow rate.
A wonderful grower that can endure tough climates? Ornamental grasses; learn more by clicking here.
The following drought-tolerant plants grow well in a dry garden.
Yarrow (Achillea millefolium) Sun-loving flowers in white, yellow, or pink pastels on feathery, aromatic foliage.
Butterfly Weed (Asclepias tuberose) Bright orange flowers in full sun throughout summer.
Yellow Epimedium (E. x versicolor 'Sulphureum') Yellow flowers in early spring. Excellent for dry shade and poor soil.
Flowering Spurge (Euphorbia corollata) Small white flowers on top of elegantly slim foliage; best in full sun all summer.
Blanket Flower (Gaillardia aristata) Showy yellow and red flowers throughout summer in full sun.
Showy Sedum (S. spectabile) Cool green succulent foliage, with late-summer bright pink flowers.
Some perennials thrive in constantly moist settings, such as bogs or marshes.
Some lovely irises like wet conditions: