Archives For Tom Weaver

Repotting Cactus

Tom Weaver —  January 10, 2017 — 1 Comment

Repotting a cactus can be intimidating, but a few simple tricks can make the project a lot less painful—and result in beautiful, healthy plants.

When repotting a cactus, there a few essential tools you’ll need:

  • Chopstick or small dowel
  • Cactus soil
  • Container with drainage
  • Gloves
  • Newspaper

Cactus soil is a special blend of potting soil that is formulated for fast drainage. It is usually a blend of peat moss and sand, sometimes including coconut fiber, perlite, or vermiculite. With the increase in popularity of growing cacti and succulents, it has become a garden center staple and can be found at most garden centers and hardware stores.

View video on our YouTube channel

You’ll want to use a container—preferably one that is made from terra cotta—with drainage holes. This allows the water to drain away from the roots rapidly. Cacti are native to dry environments and do not like to have their roots sitting in water. If the drainage hole on your pot is especially large, it can be partially covered with a rock to prevent soil from draining out the bottom when you water. Most cacti are slow growing and should never be planted in a pot that is more than an inch larger in diameter than their previous container. This is to help prevent rot.

Winter is a great time to warm up in the Greenhouses and see our cacti collection.

Weingartia lanata in bloom.

Weingartia lanata in bloom

Repotting your cactus is in many ways very similar to repotting almost any other houseplant.

  1. Begin by filling the new pot ½ to ¾ full with soil.
  2. Remove your plant from its old pot. 
    • Make sure to wear gloves.
    • Roll up a sheet of newspaper to make a strip approximately the same width as a belt. 
    • Wrap your newspaper strip around the plant and use it as a handle to gently lift the plant from the pot.
  3. If the plant is really root bound, gently loosen the soil around it to encourage new growth. (I like to leave some of the soil intact. This provides some weight to help keep the plant anchored. If the soil is poor quality, all of it should be removed.)
  4. Using the newspaper handle, set your plant into its new pot.
  5. Using the chopstick, firm the soil around the base of your plant. Keep adding soil until it reaches the same level as the old soil. (This should be approximately ½-1 inch below the lip of the container.)
  6. Water your plant throughly. 

Your cactus now has much more room to grow, which also means much more soil to stay moist. Make sure to check before watering again—the soil can stay moist for a long time, even if it is a mix made for cacti.


©2017 Chicago Botanic Garden and my.chicagobotanic.org

Some of the star attractions of Wonderland Express at the Chicago Botanic Garden are the dozens of beautiful dwarf conifers used to create Chicago in miniature. What you might not know is that many of these conifers are great plants for the Chicago area and can easily be incorporated into your home landscape.

Dwarf conifers are a good way to add four-season interest and wildlife habitat to your yard, and with their unique colors and growth habits, they are practically living sculptures. I’ve selected four of my favorite interesting and unique conifers (found in Wonderland Express—go check them out) that are hardy in the Chicago region.

Picea englemanii 'Bush's Lace'

Picea englemannii ‘Bush’s Lace’ features elegantly draping stems.

Picea omorika 'de Rutyer'

Picea omorika ‘de Ruyter’ displays bright blue needles.

Engleman spruce (Picea engelmannii ‘Bush’s Lace’) is a tall, powder blue spruce that is grown for its upright habit and pendulous side branches. Unlike some evergreens, this spruce will keep the gorgeous blue color throughout the year. This tree thrives in the extremes of Chicago’s summers and frigid winters. It is a vigorous plant and will often put on two feet of growth in one season, so make sure to plant it somewhere where it has some room. Engleman spruce are happiest in full sun with well-drained soil. A mature specimen of this tree can be found in the Dwarf Conifer Garden.

De Ruyter Serbian spruce (Picea omorika ‘de Ruyter’) is another spruce that will thrive in the Chicago region. Serbian spruce typically feature dark green needles with silver undersides that shimmer in the breeze, but on this variety, the silver is on top, making for a pop of silvery blue on each branch. This is a slower-growing cultivar, often growing only six to eight inches a year in a loosely conical shape. Because it is a spruce, it requires full sun and well-drained soil to look its best. There is also a large specimen of De Ruyter in the Dwarf Conifer Garden.

Pinus mugo 'Tannenbaum'

Pinus mugo ‘Tannenbaum’ holds its beautiful green color all winter.

Tannenbaum mugo pine (Pinus mugo ‘Tannenbaum’) is a twist on a classic mugo pine. Most people are familiar with mugo pines as the little round pines that often resemble boulders in the landscape. Tannenbaum, as the name suggests, is an upright form that grows as a perfect green pyramid, with the classic Christmas tree shape. It is a relatively slow-growing plant—approximately six inches per year—and holds its dark green color all year. Mugo pines are amazingly hardy and should do well throughout the Chicago area, provided they receive full sun and have relatively well-drained soil.

Glauca Prostrata noble fir (Abies procera ‘Glauca Prostrata’) grows as a creeping mat of icy blue foliage. Weeping blue noble fir makes an unusual addition to the landscape due to its rounded needles, unlike the similar weeping Colorado blue spruce, which has incredibly sharp needles. This makes it a far better choice for placing near walkways. This slow-growing plant averages four to six  inches of growth a year, eventually forming a clump about two feet tall and about six feet wide. As with other conifers, this noble fir prefers full sun and well-drained soil.

Abies procera 'Glauca Prostrata'

Abies procera ‘Glauca Prostrata’ stands out among the surrounding greenery.

Top tips for keeping your conifers happy:

  1. Most conifers prefer full sun and have very little shade tolerance. All of the trees in this article prefer full sun.
  2. Conifers are generally adapted to areas with well-drained soil. Avoid places that stay wet to prolong the life of your plant.
  3. Avoid windy locations. Because conifers keep their needles all year, it is best to site them in less exposed places so they don’t dry out and lose their needles.
  4. Water thoroughly in the fall. You only have once chance to make sure the plant has enough water before the ground freezes and you can’t water it anymore. If we have a dry fall, it is helpful to water your newly planted trees until the ground freezes so they have enough water to last the winter.

©2016 Chicago Botanic Garden and my.chicagobotanic.org

Christmas tree lots carry a dazzling array of trees ranging from fragrant balsam firs (Abies balsamea) to shimmering Colorado blue spruces (Picea pungens). With so many choices, how does one choose?

The three most commonly encountered groups of Christmas trees are firs, pines, and spruces.

PHOTO: Siberian fir tree (Abies sibirica).

Siberian fir
(Abies sibirica)

Fir (Abies sp.)

The most common firs available are Canaan fir, noble fir, and balsam fir. All make terrific trees with a classic piney fragrance. They feature dark green needles (often with silver undersides) and are known for their rounded needles, which minimize injuries. They’re among the longest-lived Christmas trees and most resistant to needle drop. The main downside is that some varieties can be very expensive.

PHOTO: Colorado blue spruce (Picea pugens 'Procumbens')

Colorado blue spruce
(Picea pungens ‘Procumbens’)

Spruce (Picea sp.)

Spruces come in colors ranging from dark green to icy blue, but they all share one thing in common; incredibly sharp needles. While they make terrific trees for outdoor decorating, they do not hold up very well to the dry air indoors. If you select a spruce, it is critical that it is kept away from any sources of heat that might dry it out. The branches are strong and can support ornaments well, and their color range is quite appealing. When used properly, spruce can be an excellent plant for holiday decorating.

PHOTO: Pinus cembra 'Blue Mound'.

Pinus cembra ‘Blue Mound’ from our Wonderland Express exhibition showcases its long, soft needles.

Pine (Pinus sp.)

Pines are another popular Christmas tree. The most commonly available pines are white pine and Scots pine. Pines feature long needles and tend to have a more clumpy look on the branches so the overall effect is less formal than the firs and spruce. The branches are generally more stiff than other evergreens, which makes them great for hanging ornaments. The biggest downside to pines is that they often turn a duller green for the winter. Many tree lots dye them a darker green to make them more attractive.

As you can see, every type has its pluses and minuses, but a few things hold true no matter which type of tree you select:

  1. Ask to unbag the tree before purchasing it. Many tree lots have the trees in netted bags, which makes it hard to see if the tree has a flat side or a bald spot. If this is a concern, just ask.
  2. Give the tree a good shake. If you find lots of needles falling off, that means the tree is dried out and will not last long.
  3. Look for trees with healthy, firm needles. Dull, brittle needles are a sign of a dried-out tree.
  4. Always give the trunk a fresh cut before placing it in water. If you have the ability to do this at home, that’s best, but your tree will be fine if you have it done at the lot just before bringing it home.
  5. Get your tree into water as soon as possible. Once the cut end scabs over, the tree will have a hard time taking up water and will lose needles rapidly.
  6. Never allow the water dish to dry out. It’s not uncommon to refill the dish every day, especially for the first week.
  7. Christmas tree food (a liquid food similar to the packets of cut flower food you receive in bouquets) helps extend the life of your tree.
  8. Avoid placing your tree near radiators or heating vents. This will cause needles to dry out very rapidly and can quickly become a fire hazard.
  9. At the end of the season, trees can be “planted” in the snow and used as seasonal decor and shelter for birds, or composted.

©2016 Chicago Botanic Garden and my.chicagobotanic.org

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.

Shop 200+ bulbs at the Chicago Botanic Garden’s Fall Bulb Festival, October 8–9, 10 a.m. to 4 p.m. (Members hours: Friday, October 7, 10 a.m. to 4 p.m.)

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:

  1. Cover the bottom of the pot in one inch of soil.
  2. Add your largest bulbs in a layer, leaving approximately one inch between plants.
  3. 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.
  4. Lightly water the container.
  5. 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.
  6. 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.)
  7. Once the plants begin to show flower buds, move to a less sunny location to prolong the blooming period.
  8. 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.  

PHOTO: Muscari 'Pink Sunrise'.

Muscari ‘Pink Sunrise’

Our Fall Bulb Presale ends Friday, September 30. Choose your specialty bulbs now and pick them up at the Fall Bulb Festival.


©2016 Chicago Botanic Garden and my.chicagobotanic.org

Conifornia Dreaming

Tom Weaver —  November 3, 2015 — 1 Comment

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.

PHOTO: Tour at the Golden Gate Bridge.

In the early days of colonial settlement, the hills surrounding the Golden Gate Bridge were covered with forests of lush coastal redwood (Sequoia sempervirens).

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.

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Redwoods in Armstrong Woods

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.  

Quarryhill Botanical Garden

Quarryhill Botanical Garden

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?

PHOTO: Rosa roxburghiii at Quarryhill Botanical Garden.

Rosa roxburghiii at Quarryhill Botanical Garden

PHOTO: Pinus roxburghii.

Pinus roxburghii

PHOTO: Wollemia nobilis.

Wollemia nobilis

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 Araucaria and 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.

PHOTO: Albino redwood at San Francisco Botanical Garden.

Albino redwood at San Francisco Botanical Garden

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.


©2015 Chicago Botanic Garden and my.chicagobotanic.org