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Dallas Morning News - April 17, 2019

Oak Flower Management

Trees are so cool - actually amazing, and they often surprise us. This year for example, the red oaks, live oaks, bur oaks, Mexican white oaks, Lacey oaks, and most other oaks have given us huge flower production. Why?

Management of the fallen oak flowers can vary

The yellow/beige, wormlike danglers that are by now mostly on the ground are catkins, more technically known as aments – if anybody cares. They are the male flower parts. Each of the little bumps on these catkins is a male flower consisting of a bract (a highly modified leaf), a lobed calyx and some pollen-producing stamens. I’m sure you have noticed the yellow pollen all over the place. Once the stamens have released their pollen, the entire catkins fall from the tree. The female flowers are much smaller, in fact hardly visible. They appear on new growth and are the future acorns. The amount of acorn production next fall is dependent on the quantity of the flowers and the quality of the pollination. Wind is a good thing for pollination; constant rain is a bad thing. Looks like we can expect a big acorn crop again this fall.

Why was the flower production so heavy this year? Well, since it usually has to do with the weather and soil moisture, it was probably the heavy fall rains last fall and the nicely regular rainfall we have had for the past year. Sometimes plants flower and produce seed heavily when in stress from harsh conditions. It’s a survival of the species response. But, ideal conditions without late frosts can also help create the abundant production.

Red Oak - female flowers

Female flowers on Mexican white oak

Oak flower buds are open for a short time in the spring to be pollinated by the wind. However, a late frost during the time the flowers are open can interrupt the process and greatly reduce seed (acorn) production regardless of what happens with the weather in the summer and fall.

Live oak flowers and leaves soon to be mulch

Oak flowers make excellent mulch

Management of the fallen flowers can vary but the easiest method is best. First of all - they should never be raked, bagged and sent to the landfill. They can be put in the compost pile, but the best method is to use them for mulch. Mow them into the turf, but rake the flowers from the hard surfaces and toss into vegetable gardens and landscape beds. There is nothing toxic about the material at all. The flowers make excellent mulch that protects the soil and breathes really well. As the helpful debris breaks down, it feeds the soil with nutrients and all-important organic matter. It can also be used in the compost pile, but applying directly to bare soil in beds is the best route.


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