It’s hard not to worry when your daffodils start coming up mid-winter during a warm spell. Erratic temperatures are becoming increasingly commonplace, causing all sorts of early growth in spring bulbs. Not to worry, though. Your plants have seen it all before. And they’re built to withstand all but the most extreme conditions and swings in temperature.
The underground world of bulbs
To understand why spring bulbs can withstand a little early growth, it helps to understand what a bulb is and how it functions underground.
Think of a bulb 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 them in the fall, spring bulbs start growing.
The action begins in the bottom part of the bulb known as the basal stem. During the winter, roots start sprouting from the base. As they penetrate the surrounding soil, the roots absorb water and other nutrients, which they store in the fleshy leaves of the bulb called scales.
In some flower species (think allium), 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
At the same time that the roots are expanding, the flowering shoot is also growing slowly within the bulb. Once warmer temperatures hit, the foliage begins to push out of the soil where it starts converting sunlight into energy (food) for the bulb. Finally, the flower stem bursts through the top of the bulb’s protective layer to form the plant.
The key thing to remember is: 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) to begin sending their stems up out of the bulb and 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 cool enough (40s or below at night) to plant your spring bulbs. I plant mine in early December.
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.