Now that the rainy season is officially here, weeds will explode in our plant beds. There is much ado about weeds. What can we do about them?
Water Starve Them!
We went through a very long dry spell. During that time I decided to do an experiment by withholding all irrigation in a turf alternative area I have that is mostly Mimosa strigillosa. Bidens alba is a persistent weed that constantly reseeds and likes to proliferate during the rainy season. Each morning I went out and pulled out by the root any blooming Bidens to prevent seed set. With no water, they became weak and eventually disappeared.
Sometimes by withholding water in a certain area with plants that can take it, you can eliminate those weeds that need the water to thrive.
The Mimosa took advantage of the dead and dying Bidens and filled in gaps. Remember nature abhors a vacuum and will always take advantage of spaces by inhabiting it. Planting more densely with desirable plants will keep the weed seeds from germinating. In nature, you will notice there are very few empty spaces. Use plants as a living mulch. Shading out weeds works. There are many ground covers for every situation you might encounter.
I recently attended a webinar on the best mulch to suppress weeds and one of the best is pine needle mulch. So I decided to try it in a raised bed area that is constantly inundated with Bidens, grasses, sedges and other annoying weeds, I put the mulch down very deep, 3-4 inches. Low and behold, it worked! The reason that pine needle mulch works better than other kinds is due to a simple physics principle: pine needles are cylindrical. This allows the seeds to drop down away from the light they need to germinate. Pine needles also do not retain much water and don’t break down to form “soil” as quickly as other wood mulches do. The cost is a bit more, but it’s so pleasant to work with, smells great and lasts longer.
I hope everyone reading this knows that cypress mulch is NOT a sustainable practice and shouldn’t be used in a Florida Friendly Landscape. “Several counties in Florida restrict cypress mulch use. This is done by ordinances, land development codes or regulations. Miami-Dade County’s code for new developments #1897- 15(G)(3) even says, “cypress mulch shall not be used because its harvest degrades cypress wetlands.”
Nothing can eradicate weeds like good old fashioned pulling, especially those weeds that are perennial with deep roots. Most herbicides will not completely control these. When any weed, whether a perennial or annual, flowers and then sets seed, you are witnessing the next exponential weed attack! Always pull them before they set seed and spread even more of their progeny. Pulling weeds is oddly satisfying to me. It’s also good exercise and gives me a feeling of accomplishment. Plus, it really gets the job done!
As a very last resort, you can use herbicide, but you must be very careful that you don’t create collateral damage, especially when using NON-SELECTIVE ones, such as glyphosate. Weeds are becoming resistant to this herbicide, creating super weeds, so only use this when there is no other alternative. Always remove the weeds with seeds. Weed killers do not kill the seeds, and they will quickly germinate and thrive with all the rain.
Remember, by using good cultural practices you CAN keep weeds under control.