Nine times out of ten, a SunPatiens in trouble is thirsty. These are among the most water-hungry bedding plants sold, and brown leaf edges, sudden wilting and dropped flowers almost always trace back to a rootball that dried out – or, less often, to one that never drains. Here is how to read the symptom you can see, and what to do about each.
Start with what the plant is actually showing you. Confirm with the soil check in the next section before doing anything.
| What you see | Most likely cause | First thing to do |
| Sudden wilting, soil dry | Simple drought – by far the commonest problem | Water deeply. Recovery in two to three hours |
| Wilting although the soil is wet | Roots asphyxiated or rotting | Stop watering, check drainage, look at the roots |
| Brown, crisp leaf edges | Repeated drying out, or wind | Water more often, mulch the base |
| Whole leaves browning and falling | Heat and drought together, or a cold snap | Shade in a heatwave; nothing to do about cold |
| Pale patches turning papery on top | Sunburn on a plant moved abruptly into full sun | Shade for a week, then reintroduce gradually |
| Brown or purple spots with a yellow halo | Fungal leaf spot, in damp still air | Remove affected leaves, water at the base only |
| Fine mottling, silvery sheen, webbing | %s | Raise the humidity, spray the undersides |
| Sticky leaves, curled tips | %s | Jet of water, or soapy spray |
| Ragged holes, whole leaves gone | %s or %s | Look for the culprit before treating |
| Leaves yellowing between the veins | Waterlogging, or a nutrient shortage in a tired pot | Check drainage first, then feed |
Surface soil lies. Push a finger 1 to 1½ in (3 to 4 cm) into the compost beside the plant:
In summer, a plant in a container may need water every day, and twice on a hot windy one. In open ground, twice a week is usually enough once it is established.
This is the single most searched problem with these plants, and it has four distinct causes that need four different responses.
Counter-intuitive but common, and far more serious than thirst. Roots sitting in water cannot take up oxygen, they die, and the plant then wilts because it cannot drink. Full detail in our article on root rot on SunPatiens.
SunPatiens are not especially prone to pests, but four turn up regularly.
Large caterpillars occasionally strip a whole shoot in a night. The damage looks alarming, but it is almost always the work of one or two individuals, so hunt before you spray – see our guide to treating caterpillars organically.
The good news first: SunPatiens were bred to resist impatiens downy mildew, the disease that made bedding impatiens almost unsellable for a decade. What remains is minor by comparison.
One caution on diagnosis: yellowing with irregular brown patches can also be viral, and viruses are spread by thrips. A plant that is stunted, distorted and mottled while its neighbours are fine is best removed rather than treated.
Two more articles worth having to hand: the full growing guide, and propagation from cuttings if you want to keep a favourite going.
Before anything else, put a finger in the compost. Wilting, brown edges and dropped buds all have the same first suspect, and the check takes two seconds. Treating a thirsty plant for disease is the commonest way to lose it.
Most often because the rootball has dried out at least once: the damage starts at the leaf edges and works inward, and does not heal. Sunburn gives pale papery patches on the upper surface instead; a cold night below 50°F (10°C) browns whole leaves; and a brown crust at the base usually means too much fertilizer in a container.
Check the compost 1½ in (4 cm) down. If it is dry, the plant is simply thirsty – water deeply and it will stand up within two or three hours. If it is wet, the roots are asphyxiated or rotting, which is far more serious: stop watering and check the drainage.
A great deal. In a container in July, expect to water daily – up to a litre a day for a large plant – and twice on a hot windy day. In open ground, twice a week once established. They are among the thirstiest bedding plants sold.
Usually a fungal leaf spot, encouraged by damp still air and by watering over the foliage. Remove the affected leaves, water at the base in the morning, and space the plants further apart. If the plant is also stunted and distorted while its neighbours are healthy, suspect a virus and remove it.
They were specifically bred to resist it, which is one of the two reasons they exist – the other being sun tolerance. That resistance is why they replaced ordinary bedding impatiens in most gardens after the mildew epidemic that began in 2011.
No. They are frost-tender annuals: the first frost ends them, and they are not hardy anywhere with real winters. You can, however, take cuttings in late summer and overwinter them frost-free indoors.
No. They drop their spent flowers on their own and keep flowering without help. It is worth removing dead flowers that have fallen onto the foliage, though, since they rot there and invite grey mould.
Read also:
Zantedeschia is worth a look too, for a shade-lover with the same appetite for water.
I have raised these in large, well drained containers for 3 years.
Every year several plants get some
disease that causes them to get gnarly and stop blooming.
Would appreciate suggestions on what to apply to prevent this disease.
Hi Bill,
gnarly leaves are often a sign of either some type of leaf curl, or an infestation of tiny bugs. Are there any aphids, scale insects, or mites? Sometimes they’re quite small and you need a magnifying glass to see them.
To get rid of them, a good first step is to spray leaves with water. Put a little force on the water to dislodge them, but not too much so the leaves aren’t ripped off.
Other options are described here: aphids, scale, mites. They describe many different products and tips to deal with these pests.
There is a chance that your sunpatiens is diseased, but for that it’s really important to have good pictures. If a plant is dying out, try including a picture of its roots, too.