Light: For gardens at the cooler end of the hardiness range, it will thrive in areas with anywhere from four to six hours of sun and does benefit from shade. For gardens at the warmer end of the range, it benefits from placement in afternoon shade. If they’re exposed to too much sun, they can get sunburnt. This is when the tops of the leaves have a brownish cast, and it’s a good hint that the plant needs transplanting to a shadier spot.
Soil: Prefers moist soil that drains easily. Soil pH and the presence of aluminum do affect flower color. In basic, also called alkaline, soils (pH of 7.5 or higher) the coloring will be pink. In acidic soils (pH of 6.5 or less), the coloring will be blue or purple, depending on the plant. For blue flowers, it’s also necessary to have the chemical element aluminum present.
Water: Has average water needs. It does not respond well to any period of extended sogginess, like overwatering or heavy continuous rain events.
Fertilizing: Nothing special required. If desired, you may apply a granular fertilizer formulated for flowering woody plants in late winter/early spring when the soil is workable.
Pruning: We don’t generally recommend heavy pruning. Any cuts will remove some flowering potential, this is because a good number of the flower buds are formed on old wood. You can remove dead or damaged wood at any time, just cut back to a set of leaves. If you’d like to prune to shape the plant, try to get this done when the plant is starting to break dormancy in early spring or late winter. You’ll know it’s time when the green leaf buds start to swell. To deadhead just follow the stem down to the first set of opposite leaves and cut ¼ of an inch above them.
Other: Although they make a beautiful cut flower, keep in mind that harvesting can affect the future flower display. Although it’s extremely cold hardy, you can cover it with burlap or a leaf cage during the winter if your weather gets especially harsh.