Barbara Karst Bougainvillea Shrub

The Barbara Karst Bougainvillea (Bougainvillea ‘Barbara Karst’) is a lovely crimson red blooming shrub accented with tiny white accent flowers. The bougainvillea is best for USDA growing zones 9-11 if being planted outdoors but can be container grown for growing zones 4-11. It will mature quickly to heights of 15-30 feet tall and 8-10 feet wide providing it receives the necessary full sun exposure with well draining soil. When properly spaced the bougainvillea can be used as a decorative hedge, privacy border or a beautiful standalone specimen!

Planting Directions (in ground): Bougainvilleas do best in a full sun location. Try and find somewhere that will offer at least 6 hours of direct sun every day. Ensure your drainage is good, plants do not care to be in areas where water may collect for prolonged periods. 

1) Make your hole 2-3 times the width and just as deep as the root system.
2) Bougainvilleas like a slightly acidic soil with a pH of 5.5 to 6.0 for the best results. An inexpensive soil testing kit can easily help you determine the pH range of your soil.
3) Carefully remove the shrub from its container and lightly comb the roots with your hands to help free up some of the roots.
4) Position the plant and then begin backfilling the hole with a 60/40 ratio of your native soil to gardening soil. Tamp down lightly as you fill to prevent any air pockets from forming.
5) Water the planting site when finished to settle the soil then broadcast mulch around the base to maintain soil moisture and keep competing growth such as grass or weeds away.
*Tip: Limestone can assist with increasing the pH range of your soil whereas sulfur will help lower it.

Planting Directions (potted):
1) Select a pot that is 1-2 sizes larger than the container the plant arrived in with ample drainage holes on the bottom.
2) Choose a potting soil mix with the correct pH level for the best success (5.5 to 6.0)
3) Add a little soil to the bottom of the container first so once the shrubx has been completely potted, there will be at least a one inch gap from the lid of the pot. This makes for easy watering without any mess.
4) Tamp down the soil around the rootball as you fill to ensure no air pockets have formed.
5) Water to settle the soil completely and place it in an area that will receive full sun (6+ hours every day).

Watering: Water the bougainvillea as needed. The best thing is a consistently moistened soil but NOT overly saturated. Too much water can weaken the shrub and cause excess leaf growth in place of the decorative color you’d expect.

For a potted bougainvillea, use your index finger to determine if more water is needed. Stick it into the soil down to a depth of 2 inches and feel around. If there is still moisture present, leave it be a bit longer. If it has dried out, water until you see it escaping the drainage holes and stop.

Pruning: Your bougainvillea will respond to pruning greatly when done properly. Pruning is typically done in the late fall or early winter season. Some light trimming will keep the shrub trained to a certain visual habit. Trimming removes smaller materials and gives the form a certain silhouette as well as maintain the shape. Hedge planted bougainvilleas will require some extensive pruning unless they have been properly trained along a trellis or other vertical support systems. You can remove dead wood/branches as they appear. Pruning the tips of the wood just after a bud node encourages the formation of new branches to form at the pruning junction.

Potted shrubs should have their tips pinched off monthly during their active growing season to encourage more branching. Pruning should be done after winter with sterilized clippers. Rubbing alcohol works perfectly for sterilization.

Fertilizing: During the blooming season your bougainvillea will respond well to monthly applications of fertilizer. The best results have been from 6-8-10 formulas which still allow enough nitrogen for healthy growth but also a boost of phosphorous to encourage good blooming. Discontinue fertilizing as summer comes to an end. Potted bougainvilleas do better with a balanced 20-20-20 water soluble formula applied every two weeks at half the strength recommended on the packaging.