The Warm Weather and Your Garden

The late February weather in Chicago has been a glorious time to be outside and work in the garden. But the unseasonably warm weather has also raised questions about the long-term effect on plants and what garden tasks are appropriate.

It is best to hold off on doing any detailed clean up of garden beds as the mulch and leaves in the beds will provide some protection to any early growing perennials when the weather eventually turns cold again. Raking leaves off the lawn and cutting back perennials are all fine to do now providing your garden soil is not too wet.

Snowdrops are blooming at the Garden.

Early flowering bulbs like snowdrops that are in flower here at the Chicago Botanic Garden are very tolerant of the cold. Daffodil and tulip foliage is coming up; these might end up being damaged by a spell of cold weather, but this should not affect the spring flowers. You do not need to take any special maintenance steps to protect these plants.

If you have some perennials that are growing in a warm area of the garden with more pronounced growth, they might benefit from a light layer of mulch. For the most part, though, there is nothing special for most gardeners to do in their perennial beds.

This is great weather to prune but proceed with care. Spring flowering shrubs like viburnums, lilacs, and forsythia set their flower buds last year so pruning done at this time of year will remove flower buds and reduce the number of spring flowers. You can still prune—just be aware of the flower buds as you are pruning. Forsythia flowers along the stems while viburnums will have a flower bud at the ends of the stem.

The dormant season, and in particular late winter, is the best time of year to complete rejuvenation pruning, which is the aggressive pruning of overgrown shrubs to bring them back into scale with the garden. Shrubs like hydrangea (except oak leaf hydrangea), potentilla, and spirea that flower on new wood respond well to pruning now too. For instance, I cut my Annabelle hydrangea back to the ground each spring.

Any plants installed last summer or fall should have been mulched when they were planted. If they were not, then mulch them now to help mitigate the temperature swings in the soil and prevent frost heaving of any plants in spring. The freezing and thawing of the soil can push recently installed small plants such as 1-gallon perennials or ground covers that were grown in containers out of the soil as the weather transitions to spring.

If we receive a good covering of snow, the snow itself will not harm plants unless it builds up on them and breaks branches. It is a good idea to brush plants off during a storm if you observe them getting weighted down. Later snowstorms are more likely to come in wet and heavy. Leave the plants alone if the snow has frozen on them to avoid breaking branches during the removal process.

Enjoy the warm weather and the early blooms, both at the Chicago Botanic Garden and in your own backyard.

Unexpected Signs of Spring

Sometimes spring just doesn’t want to arrive. Sometimes it can’t wait to burst forth with flowers and foliage and make everything look fresh and new. This year definitely falls into the first category, but this isn’t a bad thing. It gives us time  to appreciate some things that might otherwise be overlooked by the flashier signs of spring.

PHOTO: Red Charm Peony buds push out of the ground.
Red Charm peony buds (Paeonia ‘Red Charm’) look like alien asparagus pushing their way out of the ground in the Farwell Landscape Garden.

The cooler temperatures are slowing growth for most plants but also allowing for richer colors to develop. These peony stems have a rich burgundy color that is highly ornamental in an otherwise empty bed. Eventually these will grow out into large bushy plants with showy red flowers, but for now we can enjoy the unique form of the new growth.

Many geranium varieties also feature beautiful new growth in the spring. Geranium ‘Blue Sunrise’ in the Dwarf Conifer Garden has gorgeous bright green foliage in the summer, but in the spring it has stunning orange and red new growth that almost looks like flames coming out of the ground. Having plants with vibrant new growth can give your garden a whole new dimension. Imagine how bright blue Scilla siberica would stand out against the geranium, or how lush a planting of soft pink Chionodoxa lucillae ‘Pink Giant’ would look among the hellebores. It’s almost as though you’re getting two different plants for the price of one when you have such distinctive spring growth.

PHOTO: New shoots of Geranium 'Blue Sunrise'.
New growth doesn’t have to be dull! These Geranium ‘Blue Sunrise’ have new growth that looks like flames coming out of the ground.
PHOTO: New spring growth on Helleborus x hybridus 'Blue Metallic Lady'.
A Helleborus x hybridus ‘Blue Metallic Lady’ in the English Walled Garden sports new growth that is almost showier than its flowers.

Of course, since it is spring, there are plenty of flowers to see. Many people associate spring with bulbs, but there are some other unusual plants blooming now too. Petasites japonicus spends the summer looking like a rhubarb that has aspirations to take over the world. However, in the spring it graces us with patches of inflorescences that look like bright green cabbages. Nestled inside of the “cabbages” are clusters of lime green flowers that will gradually elongate into a short spike of tufty white flowers. They’re not the showiest flowers ever, but they have a clean, bright color that really makes them pop against the dark soil of the hillside in the Waterfall Garden.

PHOTO: Petasites japonicus has rather unusual spring blooms.
Petasites japonicus has rather unusual spring blooms.
PHOTO: Buds opening on Cornelian cherry (Cornus mas).
Cornelian cherry (Cornus mas) provides a gentle pop of spring color during a sometimes dreary time of the year.

And finally, the cornelian cherry trees (Cornus mas) in the Heritage Garden provide a soft glowing yellow that is a much gentler burst of color than the more common forsythia that can sometimes be almost gaudy with the intensity of its colors. During a time of year when so much is happening, it’s sometimes nice to have plants that allow your eyes to rest and regroup before moving on to the next batch of vibrant, eye-catching color.


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