Ask Mr. Smarty Plants

Unfortunately, we must tell you that many of the plants you have planted and/or had success with are not within the realm of expertise of the Ladybird Johnson Wildflower Center, home of Mr. Smarty Plants. We are dedicated to the growth, propagation and protection of plants native not only to North America but to the area in which they grow natively. The live oak, a real treasure, is native. In fact, every single other plant you mentioned is non-native, with the possible exception of the lantana, and it is probably Lantana camara, which is not native but widely grown in Florida and sometimes invasive there.

Without accessibility to water, you are going to have to think in terms of tough plants that will help hold the soil from erosion and keep their place all year. You don't want to hear this, but a lot of the "weeds" you are fighting are probably native grasses, which is what we would suggest for the area to begin with. If you have planted larger plants that are stunted and/or have died, it seems pointless to try to come up with others that would probably only go the same way.

A compromise solution could be to choose plants that are low water consumers, and amend the soil for each one. From e-How a video on How to Grow in Clay Soil.  Dig a good big hole, mix in compost with the dirt from the hole, and put the new plant in the hole with the "new" dirt. Water with a bucket or watering can in a slow drip letting the water soak down into that good fresh dirt. Instead of repelling rain water and/or soaking it up and drowing the new roots, you will have made a better environment for the roots,  and one which, after the initial few weeks, should make it able to thrive on rain water. If you want to keep the non-natives on which you have already spent time and money, try spreading  good quality shredded bark mulch over their root area. This will protect those roots from the heat and, as it decomposes, it will go into the soil and compost to improve that soil.

Yet another "a little bit at a time" suggestion is to build raised beds with properly amended soil, in which you can put smaller blooming plants. As you continue to add mulch and compost to these beds, the clay soil beneath will become more benign and usable. Here is an article from Popular Mechanics How to Build and Install Raised Garden Beds.

Read the comments in this Garden Web Forum on Planting in Florida Clay. Also, from eHow: Home - Plants that Grow in Clay Soil in Florida. We think you should consider some grasses in your planting. Here is an article from the University of Florida Extension Considerations for Selection and Use of Ornamental Grasses. We will show you how to use our Native Plant Database to find plants native to Florida, and perhaps you can gradually convert your clay "desert" into a pleasant garden.

Go to our Native Plant Database and, using the Combination Search, select Florida and choose a Habit (Herbs, Shrubs, Grasses, etc). There are a number of other specifications you can put in to search on, like soil moisture, light requirements, etc. but first we must find plants that are native to Brevard Co., on the middle coast of east Florida. We'll give you a sample list and you can follow each plant link to our webpage on that plant. This will tell you how much sun this plant needs, what kind of soil it can grow in, the soil moisture it needs, as well as projected height, bloom color and time and so forth.

Herbs (herbaceous blooming plants) for Florida clay soil:

 Rudbeckia triloba (Browneyed susan)

Echinacea purpurea (Eastern purple coneflower)

Shrubs for Florida clay soil:

Rhus glabra (Smooth sumac)

Amelanchier arborea (Common serviceberry)

Grasses for Florida clay soil:

Schizachyrium scoparium (Little bluestem)

Andropogon gerardii (Big bluestem)