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Crape Myrtle Problems: Why isn’t my crape flowering?

Searcy, Ark. –

I wanted to take a few minutes to draft an article about some crape myrtle problems we are seeing in this county and statewide.

There could be multiple things causing this problem:

  1. Not enough new growth during the spring flush

Recommendation: Late winter/early spring fertilization to aid in crape myrtle blooming.

  1. Shade
  • Crape myrtles require 8 hours minimum of direct sunlight daily to bloom well
  • Trees planted in areas receiving less than 6 hours of direct sun will not have good bloom development.
  • Planting tree too close together with overlapping canopies will shade out and produce less flowers – leading to uneven bloom development on the outward edges and tops of trees
  1. Insects
  • Heavy infestations of aphids decrease flowering
  • Crape myrtle bark scale is the next most common insect problem we see in crape myrtles
  • Managing the populations of these pests can help trees with flowering intensity
  • Using systemic insecticides as a soil drench has shown adequate control (Imidacloprid, thiamethoxam, and dinotefuran)
  1. Pruning
  • Drastic pruning or pruning after spring flush can delay flowering and create excessive vegetative growth and less flowering.
  • Training young plants is critical
  • Choose 5 to 7 well-spaced main leaders
  • Remove any water suckers that form at the base
  • Remove small side  branches and encourage elongation of leaders
  •  Remove branches that grown inward to maintain that vase shape
  • DO NOT TOP!
  1. Too Much Fertilizer
  • Excessive fertilizer, especially high amounts of nitrogen, can lead to excessive growth and delayed or no flowering
  • Research has shown that the ideal nutrient ratio for established flowering plants is a 3-1-2 ratio (Ex. 18-6-12)
  • From past observations, issues with fertilization and flowering are linked to not applying enough potassium when fertilizing, which leads to poor flowering
  1. Inadequate drainage/wrong site
  • Crape myrtles need a well-drained soil to flower properly
  • Water-logged soils can also impact that native soil fertility, leading to compounded issues with wrong site and insufficient fertility
  • Properly mulching around the tree will help manage soil moisture

 

By Sherri Sanders
County Extension Agent - Agriculture
The Cooperative Extension Service
U of A System Division of Agriculture

Media Contact: Sherri Sanders
County Extension Agent - Agriculture
U of A Division of Agriculture
Cooperative Extension Service
2400 Old Searcy Landing Road Searcy AR 72143
(501) 268-5394
ssanders@uada.edu

 

The Arkansas Cooperative Extension Service is an equal opportunity institution. If you require a reasonable accommodation to participate or need materials in another format, please contact your County Extension office (or other appropriate office) as soon as possible. Dial 711 for Arkansas Relay.

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