In this guide
1. Why Miami is genuinely different
Almost every piece of plant-care advice online is written for a temperate climate with four seasons, acidic loam and a winter dormancy. Miami-Dade has none of those things. We sit in USDA hardiness zone 10b, with pockets of 11a near the coast, which means frost is effectively absent and plants never fully shut down.
The soil is the bigger shock for people arriving from elsewhere. Much of the county is either sand or oolitic limestone — often both, with a thin organic layer sitting on rock. It drains extremely fast, holds very little nutrition, and sits at a pH somewhere between 7.4 and 8.3. That alkalinity is the single most under-appreciated fact in South Florida gardening, because it changes which nutrients a plant can physically absorb.
And instead of four seasons we have two: a wet season running roughly May through October, when afternoon storms can drop several inches in an hour, and a dry season from November through April, when weeks can pass without meaningful rain. Care that works in July will drown nothing in February — but care that works in February will not keep a plant alive in July.
The practical consequence. Advice that says “water when the top inch is dry” or “feed with a balanced 10-10-10” is not wrong so much as written for somebody else’s ground. Both need adjusting here.
2. Water: depth over frequency
The most common watering mistake in Miami is short, frequent irrigation. A ten-minute cycle every morning wets the top two inches of sand and nothing below it. Roots follow water, so the plant builds a shallow root plate that dries out within hours and cannot support the canopy in May.
The better pattern is longer and less often. For newly planted shrubs, a slow soak that wets the full depth of the root ball — usually fifteen to twenty minutes on a drip line, or a slow hose run — every second or third day for the first six to eight weeks. After that, taper toward twice a week, then once, letting the plant tell you when it needs more.
Check with a finger or a screwdriver rather than a schedule. Push it four inches into the bed. If it comes out damp, wait. Sand looks dry on the surface long before the root zone is dry, and a great many plants in this county are watered to death by owners responding to that surface.
During the wet season, turn the irrigation controller down or off. Rain of two or three inches in an afternoon is common, and running a scheduled cycle on top of that keeps the root zone saturated. Roots need air as much as water; in permanently wet sand they suffocate and the plant declines in a way that looks, confusingly, like drought.
3. Feeding alkaline sand
Sand holds almost no nutrients. What you apply either gets taken up or washes through, which is why a single heavy feed in spring does far less than several light ones spread across the year.
More importantly, high pH makes iron, manganese and zinc chemically unavailable even when they are physically present in the soil. This is why so many Miami plants show interveinal chlorosis — yellow leaf tissue with green veins still showing — on new growth. It is rarely a shortage of nitrogen. It is usually iron that the plant cannot reach.
A slow-release granular fertiliser formulated for Florida, containing chelated micronutrients, applied three times a year at label rate, solves most of it. Look for products where iron is listed as EDDHA or EDTA chelate; unchelated iron sulphate becomes unavailable in alkaline soil almost immediately. For a faster correction on a plant already showing symptoms, a foliar iron spray works within a week or two, but it is a patch rather than a fix.
| Symptom | Likely cause | What to do |
|---|---|---|
| Yellow new leaves, green veins | Iron unavailable at high pH | Chelated iron; slow-release micronutrient feed |
| Yellow older leaves, whole leaf | Nitrogen shortage | Slow-release granular at label rate |
| Yellow between veins on older leaves | Magnesium shortage | Magnesium sulphate, lightly, twice a year |
| Overall pale, poor growth, wet soil | Root damage from saturation | Reduce irrigation; check drainage first |
Do not exceed label rates. Excess fertiliser in fast-draining sand runs straight through to the aquifer and to Biscayne Bay, and Miami-Dade has ordinances restricting fertiliser application during the summer rainy season for exactly that reason. Check current county guidance before a heavy summer feed.
4. Mulch, and what it replaces
In a temperate garden mulch is a finishing touch. Here it does structural work: it moderates soil temperature that would otherwise cook shallow roots, holds moisture through the dry season, suppresses the weeds that colonise bare sand within days, and slowly builds the organic matter our soil does not have.
Three inches, across the whole bed rather than in rings, kept three to four inches clear of every stem and trunk. Mulch piled against bark holds moisture where it causes rot, and the resulting decline is slow enough that people rarely connect it to the cause. Our detailed mulching guide covers material choice and depth in more detail.
5. Pruning on a two-season clock
Without a dormant season, the timing rule changes. The general principle here is to prune after a flowering flush rather than before it, and to do structural work in late winter — February or early March — when the plant has the whole growing season ahead of it to recover.
Avoid hard pruning between roughly August and October. Cutting hard in late summer pushes soft new growth exactly when hurricane season peaks, and soft growth tears. It also leaves wounds open during the wettest, most fungal part of the year.
For hedges, light and frequent beats hard and occasional. Trimming a few inches several times a year builds density; letting a hedge run for a year and then cutting it back hard exposes bare interior wood that may take a full season to re-clothe.
6. A realistic monthly rhythm
You do not need a complicated calendar. The shape of the year looks roughly like this.
- February–March. Structural pruning. First feed of the year. Best planting window — warm soil, low storm risk, months of establishment before summer.
- April–May. Irrigation still needed daily-to-alternate for new plants. Watch for scale and mealybug as growth accelerates.
- June–August. Wet season. Turn irrigation down. Check drainage. Light trims only. Watch for fungal issues in dense canopies.
- September–October. Peak storm risk. No hard pruning. Thin dense tree canopies before, not during, a watch.
- November–January. Dry season begins. Irrigation back on a schedule. Second and third feeds. Good secondary planting window.
Our Miami planting calendar breaks this down further if you want month-by-month detail.
7. What to check when something looks wrong
When a plant declines, work from the ground up rather than reaching for a spray. In our experience the order of likelihood in Miami-Dade is: watering pattern, planting depth, drainage, nutrient availability, then pest or disease — in that order.
- Dig a small hole beside the root ball. Is it bone dry, or is it saturated? Both look similar above ground.
- Look at the base of the stem. Can you see the root flare, or has soil and mulch been piled over it?
- Check whether water sits after rain. If it stands for more than an hour, drainage is the problem.
- Look at where the yellowing sits — new growth or old — using the table above.
- Only then turn the leaves over and look for pests.
Our guide on why new plants fail goes through the most common causes in order, and why leaves turn yellow covers the diagnostic side in more depth.
Frequently asked questions
How often should I water plants in Miami?
Why are my plant leaves turning yellow in Florida?
What is the best fertiliser for South Florida plants?
When is the best time to plant in Miami-Dade?
Should I prune before hurricane season?
How deep should mulch be in a Miami garden?
Do I need to amend Miami soil before planting?
References & further reading
- UF/IFAS Electronic Data Information Source (EDIS) — Florida horticulture research
- USDA Plant Hardiness Zone Map
- Miami-Dade County — landscape and fertiliser guidance
Want the plants chosen for you? Tell us the space, the light and the soil, and we will put together a list that suits it — grown here, delivered here, planted here. Get a quote or call (786) 283-3401.