Geranium 'Angel's Perfume,' courtesy of Burpee
You'll catch the light, citrusy scent of lemons in 'Angel's Perfume,' a 2014 geranium introduction from Burpee. The burgundy blossoms are backed by ruffled, cool-green leaves. Best of all, this geranium can take shade to full sun. The plants grow 12" to 14" in height and width.
Image courtesy of Burpee
It’s not difficult to master wintering geraniums, thanks to their tough-as-nails constitution. By storing these plants in a dormant state or treating these annuals as houseplants, you can get a jump on next spring’s garden season—and save a few dollars along the way. Learn how to keep geraniums over winter.
Choose geraniums that belong to the Pelargonium genus for overwintering. This includes zonal or cutting geraniums, as well as ivy, scented or seed geraniums. Although Regal or Martha Washington geraniums fall into this group, they don’t usually overwinter well. Treat these cool-season favorites as true annuals and compost them when their flowering season draws to a close.
Mistake No. 1: Planting Too Late
Making late additions to the landscape can result in devastating losses next spring, especially in areas where the ground freezes. Perennials are the most susceptible to late planting, as alternating freezing and thawing of soil literally shoves plants out of soil, exposing crowns. Shrubs and trees can go into the ground later, but for best winter survival rates, you should have all plants in place by six weeks before soil typically freezes.
Mistake No. 2: Pruning Shrubs
Pruning causes plants to produce new growth, which is tender and highly vulnerable to freezing temperatures. Wait to prune shrubs, including butterfly bush and caryopteris, until spring, when all danger of frost has passed. At that point you can remove any winter killed branches. In future years, aim to get pruning done by late August, so plants have time to harden off before freezes arrive.
Mistake No. 3: Planting the Wrong Varieties
Fall lettuce crops can linger well into December in mild winter areas. Plant cold-tolerant varieties to ensure the longest harvest period. Good choices for fall planting include ‘Four Seasons’ lettuce (shown), ‘Arctic King’ and ‘North Pole.’ To overwinter lettuce in regions with cold winters, plant ‘Winter Marvel’ or ‘Brune d’Hiver.’ In mild winter areas, sow seeds of ‘Four Seasons’ or any oakleaf type.
Mistake No. 4: Not Watering New Trees
Trees that you plant in fall need consistent watering as they enter their first winter. If winter brings frozen soil without snow, give your tree a drink during any times of above-freezing temperatures. One hose-less way to ferry water to a tree is with a water bag in a cart.
Mistake No. 5: Failing to Deadhead Self-Sowers
Plants that self-sow aggressively in the landscape can be beautiful in bloom, but a gardener’s nightmare if allowed to go to seed. Clip seedheads on plants that tend to self-sow heavily in your garden. Good candidates include joe-pye weed, goldenrod, boltonia and black-eyed susans.
Mistake No. 6: Skipping Mulch
A winter mulch can be a gardener’s best friend, especially around new additions to the landscape. That extra mulch layer can help prevent frost heave around new plants that may not have an extensive root system to help keep them anchored in soil as it freezes and thaws. Put a 2-inch-thick layer around the base of plants to insulate roots.
Mistake No. 7: Spraying for Weeds
Be sure to read the label of your favorite weed killer. For common chemicals like Round-Up, 50°F is usually the lowest temperature where the product remains effective at killing weeds. Many plants essentially stop growing as soil temperatures fall into the 50-degree range, so at that point spraying is a waste of time and money. The answer is to spray early in the fall season, while plants are actively growing and air temps are still in the ideal 60-degree range.
Mistake No. 8: No Pre-Snow Clean-Up
In snowy winter climates, aim to clean up the garden before early snowfalls arrive. Doing this helps to reduce winter resting places for pests and diseases that go into hiding once snow flies. It’s also easier on you—no frozen fingers.
Mistake No. 9: Not Destroying Veggie Crops
It’s vital to destroy spent vegetable crops, especially those that hosted problem pests, like Mexican bean beetles. Don’t toss these plants into a compost pile unless you know it heats enough to destroy pests and eggs. It’s safer to dispose of infested plants and fallen leaves in bags you put at the curb for garbage pick up.
Mistake No. 10: Failing to Use Frost Blankets
If you have a garden that’s actively producing when frost threatens, there’s no excuse for not investing in some season extending equipment to keep the fresh flavors—and nutrition—coming into your kitchen. This kit costs under $25 and comes with built-in hoops and the ability to extend up to 18 feet.
Mistake No. 11: Letting Grass Grow Too Long
In snowy regions, grass that goes into winter without being mowed is more prone to develop snow mold. Try to give grass one last cut before winter snows arrive. Also, once the ground freezes, stay off the lawn. Frozen grass is more prone to breaking as you walk on it, which can damage individual grass crowns.
Mistake No. 12: Not Wrapping Vulnerable Shrubs
Take time to wrap shrubs and small trees with a winter coat of burlap for protection against cold temps. Plants at risk include those with borderline hardiness and evergreens prone to winter burn. Spray evergreens with an anti-transpirant before wrapping in burlap. Before adding the burlap, protect trunks against chewing rodents by tossing mouse bait that’s enclosed in a protective container near the base of the plant.
Mistake No. 13: Failing to Protect Trunks
As food sources become scarce, rabbits, mice and voles can make quick work of bark on unprotected trees and shrubs. Use tree guards around young tree trunks, and surround shrubs with hardware mesh. You can also try to attract raptors like owls and hawks, which prey on these mammals, by erecting artificial perch poles.
A low-effort method for wintering geraniums involves storing plants in a dormant state. Zonal geraniums yield consistently successful results with this technique due to their hearty genetics. Other geranium types may or may not overwinter well as dormant plants. This is the way that many of our grandparents overwintered geraniums, in an era when basements often had dirt floors, stone walls and high humidity. Modern basements are frequently too dry and warm to use this method.
Prepare geraniums for dormancy by lifting plants from soil. In cold regions, you can wait until a light frost zaps leaves if you want. A frost also helps by knocking down insects that might be hiding among leaves. Definitely gather geraniums before a killing frost occurs. Knock most of the soil from roots. You might want to cut plants back by one-third to one-half, but it’s not necessary.
Our grandparents hung their plants from basement rafters. In lieu of rafters, place plants into brown paper bags or boxes—some kind of container that supports plants but also allows air circulation. Check plants every four weeks. If stems start to shrivel, soak the rootball in a bucket of water for an hour or two. Allow plant and soil surfaces to dry to a dripless state before returning geraniums to their storage containers.
In spring, plant geraniums a few weeks before setting plants outdoors. Soak the rootball overnight before planting and knock off any remaining brown leaves. Take care not to damage any white or light green growing shoots. Set plants near bright windows to encourage growth. Stems will green up before new leaves start to appear.
You can also pot up geraniums and tuck them into a protected location outdoors. Just be sure to bring plants inside if a late spring frost threatens. Once plants are leafed out and growing outdoors, trim back any wayward stems or ones that failed to leaf out.
Another method for wintering geraniums is growing them as houseplants. You might want to cut plants back by one-third to one-half, depending on how much room you have indoors. Provide bright light, cool air temperatures and water only when soil is dry. Check plants carefully before bringing indoors to make sure you’re not ferrying insects inside.
Wintering geraniums causes plants to produce larger flowers as plants mature in years. This is especially true for zonal geraniums. Plants that are just a few years old can produce flower heads the size of softballs. Keeping geraniums over winter also saves money—money that you can spend on other plants for your garden.