Acanthus

Acanthus thrives in rich, fertile soil with plenty of organic matter; the soil needs to be evenly moist and well-drained. It will not tolerate wet roots, so make sure to plant it away from areas with standing water. Ensure its happiness by amending the soil with compost before planting.

Give acanthus full sun to ensure the best-looking foliage and flowers and to prevent any foliar diseases like powdery mildew. However, in warmer climates, acanthus can struggle in the hot afternoon sun and would benefit from planting in part shade. While you may sacrifice a few flowers in part sun, the plants will perform much better.

Acanthus will spread aggressively using its creeping rootstock. Because of its large size, acanthus can easily outgrow smaller, more delicate plants and can be difficult to control. When digging, if there are any small pieces of rootstock left in the soil, they can become new plants. Some gardeners plant acanthus in bottomless containers in the ground to help contain any future runners.

See more problem-solving perennials.

Acanthus spinosus is the hardiest type. It has white flowers with purple hoods on plants up to 4 feet tall. Zones 4-9

Acanthus mollis grows to 5 feet tall and produces glossy green leaves and purplish flower stems with mauve-hooded white flowers. Zones 6-10

Acanthus hungaricus bears white or light pink flowers with purple bracts on 2-foot-tall stems in early to midsummer. Zones 6-9

The inflated buds of balloon flowers are fun to pop. And they make great cut flowers. Cut them in the bud stage, and sear the base of the stems to prevent the milky sap from seeping out and fouling the water.Most commonly available in blue-violet, balloon flowers also come in pink and white, as well as shorter forms that are better suited for rock gardens and containers. In fall, the foliage of balloon flower turns clear gold, so don't cut the plant down too early -- enjoy the show! They tolerate light shade, but not wet feet or drought.

Pearly everlasting is often grown as a flower for drying, but it's so pretty growing fresh in the garden, it's hard to bring yourself to cut it and bring it indoors. This North American native looks great even in the driest of weather. Its silvery foliage and creamy white blooms make it suitable for moon or white gardens. Grow it in lean soil or divide it frequently to keep it from spreading too quickly.

There are hundreds of different spurges -- and most are valued by gardeners because they're drought-resistant and almost always ignored by deer and rabbits. Spurges are surefire picks for adding color to the garden. Many also turn gorgeous colors in the fall, enlivening the fall garden.