These 7 Plants May Not Survive a Super El Niño Winter – Protect Them Before the Cold and Wet Arrive

A very strong El Niño could make this a challenging winter for gardens across parts of the US. Repeated rain, cold snaps, and sudden changes in temperature can be especially hard on plants that need sharp drainage, so these seven are worth watching before winter sets in.

Forecasters are calling for a very strong El Niño this winter. NOAA puts the odds above 90%, and its outlook points to wetter-than-normal conditions across much of the southern and central US, California, parts of the Great Plains, and the Atlantic coast. Temperatures may vary by region, with the northern US generally expected to be warmer than normal and the Southeast potentially seeing cooler spells.

Most talk about plants for extreme weather centers on heat and drought. But a cold, wet winter is its own kind of stress – especially when soil stays saturated for weeks. Roots can’t get enough oxygen, while water molds such as Phytophthora and Pythium may trigger root rot. Freezes and thaws can then heave shallow-rooted plants out of the ground.

These seven plants tend to have the hardest time when winter soil stays cold and soggy. Most of the fixes come down to drainage, mulch and timing. Nearly all of them can be done this fall.

1. Lavender

Lavender handles cold a lot better than it handles cold and wet at the same time. Soggy, cold soil is one of the most common reasons lavender dies, since the plant is native to dry, rocky Mediterranean hillsides, where rain drains away fast.

Don't mulch lavender with wood chips or straw. Both hold moisture against the crown – a thin layer of gravel works better, like this attractive mixed pebble bag from Amazon. Stop watering once the rain sets in, and skip fall pruning so the plant isn't pushing out soft new growth right before a freeze.

Potted lavender can go under an eave or porch roof where rain won't keep soaking the pot.

2. Hens and Chicks

Hens and chicks (Sempervivum spp.) and hardy sedums can take a lot of cold, and many of them are hardy well into the North. Wet soil is another story. The rosettes tend to rot from the base up when water sits around them for days, so a mulch of gravel or grit that keeps them up off the soil helps a lot.

Potted succulents should come out of their saucers for the winter. Setting pots on Bosmere Store's Pot Toes lifts them off the patio, so water runs out the bottom instead of pooling underneath.

3. Agave

Many agaves can ride out a frost when their soil is dry, which is why some of them grow in desert areas that still see freezing nights. Cold and wet together is what tends to hurt them. A rainy winter can leave water sitting in the center of the rosette and in the soil around the roots, so agaves do best on a slope, a berm or a raised bed where rain drains away fast.

If a hard freeze shows up in the forecast, cover the plant – Walmart sells a DeWitt heavy-duty frost blanket that can be cut to size. Take the cover off once the freeze passes.

4. Garlic

Fall-planted garlic spends the whole winter in the ground. A bed that stays waterlogged for weeks can rot cloves before they ever send up a shoot, and cool, wet soil also suits white rot (Sclerotium cepivorum) if it's already in your garden.

Plant garlic in a raised bed or in rows mounded a few inches above the path. Add mulch once the soil has cooled down. Home Depot carries USA long leaf pine straw in bags, and a layer 2–4 inches (5–10 cm) deep helps even out soil temperature so freeze-thaw swings are less likely to heave the cloves up.

5. Tulips

Tulip bulbs rot easily in soil that stays wet. A long, rainy winter gives rot plenty of time to set in, and tulip fire (Botrytis tulipae) spreads more in cool, wet weather too.

Plant tulips in the best-drained spot you have, about 6–8 inches (15–20cm) deep, and don't water them after planting if the rain is already doing the job.

Beds that stay soggy are a bad bet. Containers or raised beds are safer, and hyacinths and other fall-planted bulbs need the same kind of drainage.

6. Coral Bells

Coral bells (Heuchera spp.) have shallow roots and a crown that sits right at the soil line, and that makes them one of the plants most often pushed out of the ground by frost heaving. Each freeze and thaw lifts the crown a little higher. The roots can end up exposed to cold air and drying wind.

Spread 2–3 inches (5–8 cm) of mulch around the plants after the first frost, keeping it pulled back from the crown itself, and check them after each thaw so any heaved plants can be pressed back down into the soil. Heavy, wet clay can also rot the crown. Mix in compost before planting new ones.

7. Strawberries

Strawberries can get hit from two sides in a cold, wet winter. Waterlogged soil favors root diseases like red stele (Phytophthora fragariae). Freeze-thaw cycles are the other threat – they can heave plants up and leave the roots exposed to dry out.

Raised beds help with the first problem. For the second, spread a loose layer of straw or pine straw 3–4 inches (8–10 cm) deep over the plants once they've been through a couple of light frosts, then pull it back in spring once new growth starts.

Winter Survival Essentials

Forecasts can miss. Even a strong El Niño won't bring the same winter to every yard, but gravel, mulch and better drainage don't cost much, and I'd rather have my lavender ready for a soggy winter that never shows up than lose it to one that does.