Answer: It is difficult to get a bottlebrush to fill in because once you have bare stems, they won't produce new branches or new leaves on those bare stems. The best approach with yours is to make them full on the outside so you don't notice the inside is bare. When a bottlebrush flowers, new growth is produced in front of the flowers but the stem will be bare where the flower once was. To avoid this, prune the flowering stem back to just behind the spent flower. This will result in two or more new stems. They will grow 4-6 inches long before producing another flower. When new flowers develop, enjoy them, but when they are spent, prune the stem back to just behind where the flower was. Doing this continually all summer long should help your shrubs fill out and look thick and green instead of leggy.
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