Tom Weaver is a horticulturist and takes care of the Dwarf Conifer Garden and Waterfall Garden. He has a bachelor's degree in environmental horticulture from the University of Minnesota, Twin Cities Campus. His favorite groups of plants are hardy cacti and anything with chartreuse foliage.
Why wait until spring? Plant a bulb container for a preview of blooms to come.
In this video, the Chicago Botanic Garden shows how to create a bulb garden in a pot for winter forcing so you can enjoy a preview of spring in the midst of winter’s chill. Forcing is the act of putting plants through a cold period in order to stimulate blooming during an atypical time of the year. By potting up your bulbs now, you’ll be able to enjoy a spring garden in your living room in ten weeks.
What you need:
A shallow container with drainage holes
Enough spring bulbs to fill the container (plan on planting them close together, with an inch of space between bulbs)
Slightly moist potting soil
Assemble your container:
Cover the bottom of the pot in one inch of soil.
Add your largest bulbs in a layer, leaving approximately one inch between plants.
Cover these bulbs. If adding another layer of smaller bulbs, leave 1½ inches of space from the top of the pot. Add the small bulbs in this layer, leaving one-half inch of space between plants. Fill with soil to within one-fourth inch of the rim.
Lightly water the container.
Place your container in a cool, dark location. The container must never get above 50 degrees or below freezing. Ideal spots are an unheated garage or, if you do a small pot, the crisper drawer of your refrigerator.
In ten weeks your plants can be moved to a warm, sunny location. You should start to see growth within a week. (If you don’t want to bring your plants out at this time, they can hold for several months in a cool location.)
Once the plants begin to show flower buds, move to a less sunny location to prolong the blooming period.
After blooming, plants should be discarded. Forced bulbs rarely transplant well into the garden.
The best plants for forcing tend to be on the smaller side. Tulips and narcissus work very well, especially the smaller cultivars. Larger blooms will require staking, especially if they don’t receive enough sunlight. Iris reticulata, Scilla siberica, Crocus, and Muscari are all wonderful bulbs for forcing: they stay small, and come in beautiful jewel tones that will brighten up any winter windowsill.
In early September, I had the privilege of attending the annual meeting of the American Conifer Society in Sonoma County, California. My first (and wildly inaccurate) thought was, “What could we possibly see aside from redwoods? There aren’t any conifers that thrive in that area.” Well I couldn’t have been more wrong, as the next two days showed me.
Our first day included stops at one private garden, Hog Hill; a trip to an old growth redwood forest; and a very informative demonstration by the Aesthetic Pruning Association. Hog Hill is notable for having a dawn redwood (Metasequoia glyptostroboides) that is likely one of the very first grown from seed after being rediscovered in China in 1941. The rest of the garden featured a wide array of South African and Mediterranean plants that were well suited to the semiarid climate.
The part of the trip I was looking forward to most was next. After waiting my entire life to see them, I was finally getting to see coast redwoods in their home. While I’ll never be able to grow them here in the Chicago area, it was still inspiring to see such majestic trees in person. Armstrong Woods State Natural Reserve was owned by a lumberman in the 1880s who recognized the area’s beauty and set aside this tract of land as a public park. While it doesn’t contain the largest trees in California, it still is home to an outstanding number of trees. Nothing reminds you of how big the world is like standing next to a plant more than 300 feet tall! We also had a chance to take a guided walk with docents from the park, where we learned that the vast majority of wildlife resides way up in the canopy, which explains why the forest floor was so eerily silent.
After touring the redwoods, we traveled to Circle Oak Ranch, an equine center that also features an amazing collection of dwarf conifers. Unfortunately, my camera’s battery was dead by this point, so I don’t have any photos to share. We were treated to a tour of the gardens followed by an outstanding pruning demonstration by the Aesthetic Pruning Association. Several volunteers were stationed throughout the gardens giving demonstrations on how to properly prune various growth forms of dwarf conifers. This garden was also a highlight, because it was located in an area that experiences colder temperatures and heavy clay soil, and therefore featured numerous plants that would also thrive in our midwestern climate.
The following day was a trip to Quarryhill Botanical Garden. Quarryhill features a vast collection of temperate climate Asian plants. More than 90 percent of the plants were grown from wild collected seed in places ranging from Japan to India. The gardens date from the late 1980s, when the property owner at the time decided to convert the abandoned rock quarries on her property into a lush garden. Quarryhill included many unusual conifers in their collection, which made it a great opportunity to see plants I will likely never see again such as Pinus roxburghii and Cupressus chengiana.
However, I will admit that my favorite plant from the garden ended up being—of all things—a rose. Rosa roxburghii features very large (nearly golf-ball-sized) hips of vibrant yellow with small, reddish spines covering their surface. Sure, it might not be conifer-relevant but it never hurts to learn a new plant, right?
Our final stop on the trip was the San Francisco Botanical Garden (formerly Strybing Arboretum). Their 55 acres packed an incredible number of plants into one place. The conifer highlight of the garden was a very rare albino redwood. Unable to survive on their own, albino redwoods are mutations that lack chlorophyll, typically found growing at the base of an otherwise normal redwood tree. Other highlights included some magnificent specimens of conifers from the Southern Hemisphere including Araucariaand Wollemia nobilis, a tree that was only known from the fossil record until 1994, when a small grove was discovered near Sydney, Australia. We are fortunate to have a specimen of Wollemia on display in our Heritage Garden as well, but it was exciting to see a larger specimen such as this.
In addition to seeing such an amazing array of plants in two days, this trip also gave me the opportunity to meet dozens of other professionals and hobbyists who share my love of conifers. The amazing thing about trips like this is seeing just how much there is in our world and how important it is to share ideas and see new things. If I had never taken this trip I would probably go on thinking that everything in northern California east of the coastal hills was a barren grassland, not an area teeming with native plants, and I never would have had a chance to meet so many interesting people, each with their own unique take on the world of conifers.
Early summer in the Dwarf Conifer Garden is all about the new growth. Everything is bursting forth with fresh new growth in vivid shades of green, chartreuse, yellow…and blue!
Many of the trees feature entirely unexpected colors. For most of the year, Spring Ghost blue spruce (Picea pungens ‘Spring Ghost’) looks like your average Colorado spruce. From early spring through midsummer, however, the tips of every branch shine with the palest yellow—nearly white—new growth. Likewise, Taylor’s Sunburst lodgepole pine (Pinus contorta ‘Taylor’s Sunburst’) is a handsome green tree for most of the year—until spring, when radiant yellow new growth bursts forth, bringing a welcome dose of sunshine to the garden.
New needles aren’t the only attraction this time of year. Many conifers have cones that start out in surprising shades! Blue Mound Swiss stone pine (Pinus cembra ‘Blue Mound’) would be a beautiful plant in its own right, with its long, soft, blue-green needles. But when you throw in dusky purple cones, you get a plant that is truly a gem. As the cones age, they’ll slowly turn into the more typical brown of a ripe cone, but right now, they’re as pretty as any flower.
Red can be a difficult color to find in conifers, but Acrocona spruce (Picea abies ‘Acrocona’) has cones that start out a vivid ruby red and slowly fade to a soft tan. The cones start out upward-facing, but slowly begin to droop as they age.
Another unique plant is Silver Show dwarf Korean fir (Abies koreana ‘Silver Show’). Unlike other conifers, the firs (Abies sp.) have cones that always face upward. ‘Silver Show’ is beautiful any time of the year, but its purple upward-facing cones really make it special in spring. The cones start out small and green, but as you can see in this picture, they begin to turn purple as they grow until you’re left with dozens of dark purple cones set against perfectly tiered, silvery green foliage. There really is nothing else like it in the Garden.
On most conifers, it’s the female cones that are most showy and most often noticed, but on Bosnian pine (Pinus leucodermis), it’s the male (pollen-bearing) cones that steal the show. Arranged in groups at the end of every branch, they light up the tree like little Christmas lights. Even on a gloomy day, the bright orangey-tan color stands out against some of the deepest green needles in the garden.
All of these colors are a seasonal show that is best appreciated before things start to heat up for the summer, so now is your best time to come see them!
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.
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.
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.
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.
It may be 5 degrees Fahrenheit outside right now, but that’s not stopping the Dwarf Conifer Garden from shining.
In fact, many of the conifers are at their peak during the coldest weather. While other plants have gone dormant for the winter, various conifers are lighting up the landscape in shades of blue, yellow, bronze, plum, and more.
Arborvitae (Thuja sp.) are among the best evergreens for bright winter color. Cultivars such as Thuja occidentalis ‘Golden Globe’ provide a burst of gold while other varieties turn shades of bronze or deep green.
Pines (Pinus sp.) also provide a winter show with species such as Pinus sosnowskyi and Pinus sylvestris showcasing powder blue needles and beautiful brown bark. Others, such as Pinus virginiana ‘Wate’s Golden’ turn to a soft yellow hue that lights up the garden.
Among my favorite evergreens for winter interest are the firs (Abies sp.). Korean fir (Abies koreana) has needles that curl upward tightly, showing off silvery undersides and giving the plant a clean, tidy appearance. They also grow into a classic pyramid shape with little to no pruning, making them great for low-maintenance settings. Other firs have long, upturned needles that catch large amounts of snow. Some are the most clean, bright, silvery blue, and others have beautifully deep green foliage all winter long.
Other groups of conifers such as larch (Larix sp.), Douglas fir (Pseudotsuga sp.), yews (Taxus sp.), and more each have their own unique growth habits that provide valuable winter texture and create strong focal points. Some of them (such as larch), lose their needles for the winter, leaving you with skeletons of copper-colored branches, while others (such as Douglas fir), are laden with unique cones. Still others (such as yews), that spent all summer providing a nice green backdrop are suddenly a sturdy focal point where your eyes can rest as you view the landscape.
The Dwarf Conifer Garden is full of dozens of varieties and species of conifers in all shapes and sizes. While the rest of the Chicago Botanic Garden slumbers under a thick layer of snow, this one is at its peak, waiting to show off shapes and colors that almost don’t seem real.