Skip to main content
St. Augustinegrass

Q: Is there anything I can do to “encourage” my thin, weedy lawn?

Q:  I just purchased a property on Amelia Island.  The lawn has been neglected for a number of years.  It is St. Augustinegrass but in places very thin and of course, weedy.  There are a number of large trees to shade which is a problem as well as the leaves.  I’ve been raking leaves and applying a “weed and Feed” product for Southern Lawns.  I believe the irrigation system is working OK. Is there anything else I can do to “encourage” this lawn?

A:  Welcome to Nassau County. The areas of grass are thin under trees probably because St. Augustinegrass prefers full sun, although 2 varieties (Bitterblue and Seville) will tolerate some shade.  Grass grown under trees will typically last a few years but become thinner each consecutive year.

Consider planting something else in the area before the weeds completely take over.  You might also expand the beds under your trees with mulched areas – just be sure to keep the mulch away from the trunk of any tree or shrub.  Some good ornamental alternatives to St. Augustinegrass would be mondo grass, asiatic jasmine, holly fern or dwarf liriope.

One other thing, the University of Florida does not recommend the use of “weed and feed” products on St. Augustinegrass – the nitrogen amount is too high compared to the phosphorus and potassium.  Consider fertilizing it with a complete fertilizer such as 15-0-15.  Look for fertilizers that have a high percentage of slow release nitrogen too – we prefer 1/2.  We suggest you fertilize in March, May (if you feel you need to) & September.  Use Ironite only in the summer which should contain little or no nitrogen.

Water in the morning hours between (6am-10am); apply about 3/4 inch to 1 inch once every 5 days or as needed. If the blade of grass is nice, full and green it does not need to be watered.   Shaded areas need less water and fertilizer than plant material in full sun.

One other thing, please do not add lime to your yard unless a soil pH test indicates you need it. Although this is a common practice for grasses up north, it is not advisable for lawn grasses here in the south.  I will be giving a class on June 22 at the Yulee office at 9am – consider coming in to discuss your specific problems.  The class is free and I encourage participants to bring in grass samples (soil, root and all) so we can learn how to check for problems.