In my neighborhood in Alexandria, I’ve seen winter jasmine, quince and spring camellias in full bloom, Carolina jessamine breaking bud, and perennials like coneflower and Japanese anemone emerging as though it’s April. My own climbing hydrangea has swollen leaf buds. Don’t these plants know they are supposed to be dormant? What’s going on?
The extraordinarily mild and wet December brought to us by El Niño may have triggered some plants to break dormancy, tap into their stored sugars and begin their yearly cycles of growth and bloom. Unfortunately, now that cold weather is upon us, much of these tender buds, blossoms and leaves are going to be killed. It only takes one or two nights dipping down in the 20s for beautiful flowers and foliage to turn into brown mush.
Plants, however, are resilient! Few, if any, hardy plants will be be killed outright in this cold snap, though you may notice the implications for months to come. Below is a quick guide to what you can expect to see and what you can do to help plants recover from any damage. Keep in mind, the wacky weather was the warm December, not this week’s cold.
What Do These Occurrences Mean?
Full Blooming Plants
Enjoy them while they last. Most blossoms will turn to mush in the next few days. For plants that have only one set of annual flowers, that was it. Don’t be alarmed if you don’t see a thing at their usual bloom time. Expect them to set buds on schedule for next year. For plants that have multiple or continuous blooms, you may see a reduced bloom on schedule or a delayed bloom. A few plants have cold-hardy blossoms and might just make it through. Feel free to pick/trim off any zapped blossoms that you find unsightly. They are not coming back, and you will not hurt the plant.
Breaking/Swollen Flower Buds
Expect them to be killed, probably. If you look carefully, you will see that they lose their vitality and dry out over the next week. Once this happens, they will not open. However, buds that are not killed should open on schedule. Again, it is fine to pick off killed buds if you are sure they are dead.
Swollen Leaf Buds/New Growth on Woody Plants
Expect some to be killed and for plants to be a bit depleted. Plants that are truly breaking dormancy or never went dormant are a bit more problematic than those that are merely blooming. If leaf buds on deciduous plants swell enough or open, and if evergreens generate new growth, all of this tissue will not be hardy enough to withstand the cold. Expect it to be burned or killed and to turn brown and dry out back to the point of older growth, which had a chance to harden off. The rest of the plant should be unaffected. In the case of leaf buds, the plant will generate new ones to replace the ones that are killed; however this may take time and cause the plant to leaf out later than usual in the spring. Similarly, in the case of new growth on evergreens, the spring flush will occur but may be delayed. Feel free to remove unsightly dead or burned foliage at any time.
Because any flush of growth depletes the energy and nutrients plants have stored in their roots, you also may want to give the plants some fertilizer to help restore what was lost. A general purpose slow-release fertilizer, such as Merrifield Tree & Shrub Food, is all you need, and it can be applied anytime the temperatures are above freezing between now and early March to ensure a verdant growing season.
Emerging Perennial Foliage
Don’t get excited, it’s about to go away again. Also, don’t be worried. The plant will come up again in the spring, though it might be a bit late, and it should bloom per usual. As with woody plants, perennials used energy and nutrients to break dormancy and produce those new leaves, so they will probably benefit from a dose of slow-release fertilizer, such as Merrifield Flowering Shrub Food. Apply as above. Remove dead perennial foliage anytime to keep planting beds looking neat and clean.
Sit tight. Bulbs that come up early on a warm winter day are not terribly unusual. Generally, they are hardy enough to withstand cold, snow and ice and be no worse for the wear when the weather warms again. If flowers have fully opened, they may be lost for the year as with the blooming woodies. Should they give you a second round of growth and flowers in spring, their stored energy will likely be spent. Be sure to fertilize so that the bulbs have enough nutrients and energy for the following year.