(Last week it was 70 degrees, now it’s 20)
Let’s face it. It’s hard not to stress when your daffodils start coming up mid-winter during a warm spell. With all the erratic weather we’ve been experiencing lately, early growth is becoming more and more common in spring bulbs. Not to worry, though. Your plants have seen it all before. And they’re built to handle a few temperature swings.
The underground world of bulbs
To understand why spring bulbs can weather a little early growth, it helps to take a peek underground.
Just like a seed, a single bulb contains the entire life cycle of a plant, including roots, food storage “leaves” and a flowering shoot. As soon as you plant it in the fall, a spring bulb starts growing.
The action begins in the bottom part of the bulb known as the basal stem. During the winter months, roots begin emerging from the underside of this base. As they penetrate the surrounding soil, they absorb water and other nutrients, which they store in the fleshy leaves of the bulb called scales.
In some flower species like alliums, a thin papery covering called the tunic protects the bulb’s scales from damage and drying out.
Papery thin tunic keeps bulbs from drying out
The scales’ job is to provide food and protection to the flowering shoot, which contains all of the above-ground parts of the plant, including stems, leaves and flowers. During the winter months, the shoot slowly grows upwards within the bulb underground.
In the spring, as temperatures rise, the bulb’s biological clock tells its leaves to break through the soil where they begin converting sunlight into energy for plant growth. A few weeks later, the flowering stems begin to emerge.
The key thing to remember is this: Leaf development occurs independently of flower development. The leaves might jump the gun, but flowering shoots need an extended period of time (between 5 and 7 weeks) before they begin sending their stems up towards the surface. Before that happens, the bulb has most likely weathered the warm spell and resumed dormancy.
Strategies for protecting early growth
If you see foliage poking up out of the ground too early, don’t worry. A cold snap may cause its leaves to yellow and die back, but your bulb will wait things out and send up new growth once temperatures warm up again.
There are a few strategies, though, you can undertake now to slow things down while adding an extra layer of protection to the flower shoot.
1. Cover your plant
Covering the soil around your spring bulbs will provide insulation against frigid temperatures and drying winter winds. Try mulch, straw, bark chips, leaves or pine needles.
Or, if the plant is budding too early, try draping a cloth over it (securing it above the plant with stakes.) Remove the drape during the day so the foliage can absorb sunlight to warm back up.
Bulbs will rot with too much water, but if there’s been a dry period for a long period of time, providing them with a little extra water during the day helps the bulb expand and grow. Make sure your soil has good drainage, though.
3. What to do if flowers start to appear
If the weather continues to stay unseasonably warm, your spring bulbs may start to produce flowers. Don’t worry. Even if frost kills off some of the initial buds, it usually doesn’t affect flowering in the coming months.
4. Plant bulbs late in the fall
The later you plant in the fall, the longer the bulb will take to sprout in the spring. Wait until the temperature is cold enough (40°F or below at night) to plant your spring bulbs. This will ensure they are fully dormant.
And make sure to plant bulbs at three times their height in depth with base down and bud up. Planting bulbs too shallow can cause premature growth.
For a list of popular spring bulbs and an expert’s recommendations on when and how to plant them, click here for my November post Spring Bulbs: Still Time To Plant These 10 Great Varieties.