(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. As weather becomes more erratic, 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 tolerate 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. This includes 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 called the basal stem. During the winter months, roots begin emerging from the stem to penetrate the surrounding soil. As they grow, 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
In addition to food storage, the scales provide 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.
Finally in the spring, the bulb’s biological clock tells its leaves to break through the soil, where they begin converting sunlight into chemical energy the plant uses to grow. Approximately one month later, the flowering stems begin to emerge.
At this stage in the process, 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 leaves to yellow and die back, but the bulb will wait things out and send up new growth once temperatures warm up again.
There are a few strategies, however, that you can implement 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.
2. WATER DURING DRY SPELLS
Although they’ll rot with too much water, if there’s been a dry period for a long period of time, a little extra water during the day helps bulbs grow. Make sure your soil has good drainage, though.
3. 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 won’t affect flowering in the coming months.
4. PLANT BULBS LATE IN THE FALL
The later in the fall you plant, the longer the bulb will take to sprout come 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. I plant my many different daffodil varieties as late as mid December here in Maryland.
Finally, make sure to plant your bulbs at three times their height in depth with the base down and the bud up. Planting bulbs too shallow can lead to premature growth.
For a list of ten popular spring bulbs and when and how to plant them, click here.