Archives For Horticulture & Display Gardens

Learn more about the plants and gardens at the Chicago Botanic 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.

Demystifying Seed Catalogs

Get seed catalog savvy

Lisa Hilgenberg —  February 16, 2017 — 6 Comments

The arrival of seed catalogs in mailboxes ranks as one of the most hopeful times in a gardener’s year, as it provides us with a welcome link to spring.

February is the perfect time to plan next spring’s vegetable garden. One of the first considerations is deciding what to grow. This can be answered by simply listing the veggies or asking your family to name the veggies they like to eat. There are a few other considerations before placing your order for next year’s garden—such as deciding if you should plant seeds or transplant vegetable starts. Seeds of many vegetables can be sown directly in the garden, including root vegetables like carrots, radish, and beets. Peas, beans, and squash are also best directly sown. Cabbage, tomatoes, and peppers are better given a head start inside first, and then transplanted into the garden as small plants, because they need a long, warm growing season.

Brassica oleracea 'Blue Wind' broccoli

For spring plantings, set broccoli transplants out two to three weeks before the last spring frost date.

PHOTO: Planter potted up with edible greens.

Edible spring planters can be harvested and repotted with next season’s veg.

Timing is important in the vegetable garden, and knowing that our growing season has approximately 170 frost-free days helps guide decisions on which plants to plant and when to plant. Our risk of frost is generally from October 15 through April 27, but can vary two weeks in either direction. Understanding that vegetable varieties have varying tolerances to frost helps you plan your planting calendar. For example, those very hardy plants like collards, kohlrabi, kale, spring onions, pea, spinach, turnip, and cabbage can be planted out four to six weeks before our last frost date. Those called “half hardy” or “frost tolerant”—such as beets, Swiss chard, carrots, cauliflower, and mustard—must be planted a bit later; two to three weeks before the last frost date.

The best seed catalogs will help decipher a gardener’s questions, and help plot, measure, and sort out the seed math needed to get started on a vegetable garden. Most seed is available in organic and non-organic options, with the latter usually the least expensive. Good catalogs provide keys to help decipher the icons (vegetable resistance codes) in plant descriptions. After all, a seed company’s success is based on a gardener’s success with their products.

As our nutritional consciousness rises, the taste and the health benefits of growing your own organic produce is a pursuit worthy of winter afternoons spent planning.  

Here are a few of my favorite seed companies:
(Consider going paperless; all of these catalogs are available online.)

Johnny’s Selected Seed
www.Johnnyseeds.com (877) 564-6697

Johnny’s Selected Seed is a 43-year-old, employee-owned company in Maine, recognizing that “good food is the basis of our well-being.” Widely used by home gardeners and small market farmers, the seed selection includes hundreds of vegetable, flower, and herb varieties in organic and non-organic (options) seeds. The catalog provides grower’s information for the novice to advanced gardener—it’s a virtual garden education. Johnny’s provides well-tested tools for garden tasks from bed prep to trellising, to season extension, and cover cropping. Comparison charts like the one on leaf lettuce help gardeners select seeds based on their specific growing conditions. Charts and photos compare length, width of mature veggies, and harvest windows.

High Mowing seed catalogHigh Mowing Organic Seeds
www.highmowingseeds.com (866) 735-4454

High Mowing Organic Seeds simply provides 100 percent certified organic, non-GMO Project Verified vegetable and flower seed to organic growers. The helpful seed catalog key on page two of the new 2017 catalog includes a tutorial on how to read the individual variety descriptions that follow. Seed definitions of open pollinated (OP), heirloom, and hybrid seeds are aptly explained and marked throughout. Crop types are headed by general cultural information or the “how to” grow beans for example. Then each listing is complete with the days to maturity (based on conditions in Vermont where HMO is located), disease resistance and any special attributes of the plant including breeder credit. Don’t miss the invaluable planting chart on the last page. High Mowing Organic Seeds is an excellent resource for passionate organic growers.

The Cook’s Garden
www.cooksgarden.com (800) 457-9703

Burpee acquired The Cook’s Garden more than ten years ago, and it has helped nurture America’s love affair with healthy, delicious food by offering the best gourmet veggies, greens, and herbs from around the world. The catalog offers seeds and plants for gourmet gardeners, with vegetables and fruits often pictured in recipes alongside culinary tips. Offering well-curated collections of helpful horticultural gadgets, you’ll find ash-handled tools, trellising supplies, rain gauges, and garden hods (flat, wood-handled basket) to make harvesting a snap. The Cook’s Garden catalog offers a wide range of quality products to indulge your inner gardener-chef when produce arrives in the kitchen. They’ve got canning, preserving, and dehydrating supplies covered. If the ultimate luxury is having the right tool for the job, check out the herb snips, the strawberry huller, and my current obsession, the new pickle slicer.

Seed Savers Exchange
www.seedsavers.org (563) 382-5990

Seed Savers Exchange helped start the heirloom seed movement by locating and preserving almost 20,000 varieties by growing them and seed banking at Heritage Farm in Decorah, Iowa. The not-for-profit’s mission is to conserve and protect America’s culturally diverse but endangered food crop heritage for future generations by collecting, growing, and sharing open pollinated seeds and plants. The catalog contains an anthology of stories and fascinating anecdotes connecting the reader to plant history, and has a comprehensive roster of vegetable seed many of which are certified organic. Be sure to check out the heirloom flower seed, garlic, and seed potatoes. It’s a great resource for seed saving supplies and helpful guides to get started planting and seed saving.

Pinetree Garden Seeds catalogPinetree Garden Seeds and Accessories
www.superseeds.com (207) 926-3400

Pinetree has been a year-round source for the home gardener for more than three decades. Their product lines go well beyond a fairly complete line of gardening gear, including soil kits and amendments, and animal deterrents. Also offered are natural bath and hair products, kitchen gadgets (I want the tortilla press), and bee, bat, and bird products. If you’d like fragrant oils and herbal teas to go along with your vegetable seeds, look no further than Pinetree. There is a comprehensive compendium of some of the best gardening books that I’ve seen.

Baker Creek Heirloom Seeds
www.rareseed.com Fax: (417) 924-8887

Baker Creek offers 1,800 vegetable, flower and herb varieties claimed to be the largest in our country.  A focus on preservation, it not surprising they have one of the largest selections of seeds from the nineteenth century. The fittingly named Rare Seed Catalog is like the Vogue magazine of the vegetable world. It wins the prize for the most beautiful photographs of the most avant-garde produce collection, complete with nutritional factoids and culinary inspiration. Stories from seed collecting expeditions around the world—recently Thailand, Myanmar, and India—are in the Heirloom Gardener, an associated and nationally distributed magazine written as a tool to not only promote and preserve our rich agricultural history but as explanation of why we need to care about it. The Rare Seed Catalog provides a selection of 78 varieties of melon and 20 types of okra. Baker Creek has a limited but diverse availability of live plants to ship. If goji berries, ginger root, and dragon fruit tickle your fancy (and you either live in the subtropics or have a greenhouse available) look no further, they’re in the Rare Seed Catalog. Baker Creek encourages political activism, and the catalog is written with an underlying ripple that we’re reaching the tipping point in the struggle against GMOs.


Specialty catalogs

Vermont Bean Seed Company
www.vermontbean.com
Bush or pole? Round, broad, or flat-podded? Shellers or runners? Golden, purple, filet, or lima—Vermont Bean Seed Company’s catalog for home gardens has them all. 

Filaree Garlic Farm
www.filareefarm.com
Garlic immersion is made possible by paging through the Filaree Garlic Farm catalog. A certified organic garlic grower in Washington State, Filaree encourages placing early orders of favorite rocaboles, porcelains, and purple stripe garlic.

Totally Tomatoes
www.totallytomato.com
Whether you are growing tried-and-true tomato varieties or venturing on to new releases and heirlooms, Totally Tomatoes offers hundreds of tomato varieties to the avid tomato grower. Categorized by size, shape, and color, Totally Tomatoes is a veritable rainbow for the tomato connoisseur. Focusing on Solanaceous crops, dozens of pepper varieties are included, too. 

PHOTO: A basket of garlic, with each bulb labeled with its cultivar name.

Try growing different garlic varieties to find the flavor you like best.


Varieties/cultivars and tips for direct seeding into spring gardens

It’s hard to resist a list of a few of my favorite varieties to directly sow into the spring garden. Knowing how much seed will sow a 10-foot row and the days to maturity (when the harvest can be expected) is the type of garden math that tangles up many a gardener, but quality catalogs will provide vegetable grower’s guides to help to sort out how much seed you’ll need. 

Radish: Direct-sow spring radish as soon as the ground can be worked, or four to six weeks before the last frost. Radish is best grown quickly in cool, damp conditions. It’s easy to grow, and requires only 28 days from planting to harvest. Try these spring radish cultivars: ‘Early Scarlet Globe’, ‘Rudolf’, and ‘Crunchy Royale’.

PHOTO: Beets.Beets: Nothing says spring like tender, freshly harvested baby beets. Sow about two weeks before our last frost date and thin to 3 inches between seedlings. Fertilize with liquid seaweed. Beets have great culinary versatility, so plant a combination of gold and red. ‘Detroit Dark Red’, ‘Bull’s Blood’, and ‘Burpee’s Golden’ are great choices.

Swiss chard: We love ‘Rhubarb’ and ‘Five colored Silverbeet’. These greens can grow through the entire gardening season. By harvesting just the outer leaves with a harvest knife, the plant stays in place and the integrity of your design stays intact.

PHOTO: Carrots.Carrots: The sweetest, juiciest, and most flavorful carrots are the French heirlooms. Sow two weeks before the last frost date. Carrot is slow to germinate, so have patience. Our favorite varieties for Chicago growers: ‘St. Valery’, ‘Paris Market’, and ‘Scarlet Nantes’.

Spinach: One of the earliest-germinating cool season vegetables, spinach can be direct sown in 2-inch bands or rows four to six weeks before the last frost. Plant ‘Corvair’, ‘Tyee’, or ‘Donkey’ for the most reliable spring crops.

Lettuce: We love ‘Tennis Ball’, ‘Black Seeded Simpson’, ‘Rouge d ’Hiver’, and ‘Winter Density’. One gram of seed will sow a 15-foot row.

Spring greens: Try mache, arugula, or mizuna; 30 to 50 seeds will seed one foot of row when sown as a cut-and-come-again salad mix.


©2017 Chicago Botanic Garden and my.chicagobotanic.org

Seed saving is an art, not to mention fun and empowering. Plus, it’s a valuable contribution on a deeper level: agricultural biodiversity matters, and seed saving in home gardens is mainstream conservation of biodiversity!

PHOTO: John Withee bean collection.

A highlight of our 2013 Seed Swap was the John Withee bean collection. A family tradition of “beanhole” cooking led John Withee to collect and organize 1,267 bean varieties. He donated the collection—and its handcrafted case—to Seed Savers Exchange before he passed away.

Here’s why you, the home gardener, should start a seed collection:

Seed saving promotes self-reliance, and swapping seeds connects and builds community. It connects us to our agricultural roots. Additionally, it helps conserve our agricultural resources. Preservation matters. Once varieties are lost, they cannot be recovered. A century ago, seed houses had hundreds of varieties, and now just a few remain. Think about this vegetable fact: In 1903, 544 varieties of cabbage were listed by seed houses across the United States. By 1983, just 28 of those varieties were represented in our national seed bank at the National Seed Storage Laboratory (now the National Center for Genetic Resources Preservation).

Saving seeds encourages adventurous eaters. Growing heirloom varieties holds culinary appeal because it offers the opportunity to grow interesting vegetables that aren’t readily available in grocery stores.

Thrifty seed collectors save money because there is no seed to buy each spring. They maintain a personal seed collection.

Seed savers are lifelong learners, and home gardeners play an important role in helping to preserve our diverse seed histories. Home gardens become living laboratories to learn about plants. Seed saving builds observation skills, and there is a need for more seed growers to evaluate varieties for disease resistance and variety. 

Finally, saving and sharing seed just feels good. 

PHOTO: Broccoli seedlings

Broccoli seedlings

Which seeds should be saved (and are the easiest to save)? 

Deciding which seeds to save requires a working knowledge of several definitions:

Hybrid varieties (F1) produce seeds that, when grown the next year, are unlikely to resemble the original plant. Don’t save seeds from a hybrid vegetable. Seeds should be saved from open-pollinated plants (OP), those stable varieties that can reliably reproduce themselves generation after generation. As long as open-pollinated plants don’t cross pollinate with other varieties of the same species, their offspring will carry the distinguishing characteristics of the variety. Heirloom vegetables are open-pollinated plants that produce seeds passed down from one generation to another, often with historical connections and stories. Heirlooms carry special value and are usually old varieties.

Deciding which seeds to save requires a basic understanding of how plants reproduce:

Very simply, plants either mate with themselves or they mate with other plants. Self-pollinating plants have all the flower parts (anther and stigma) to transfer pollen within their own flowers (achieved by physical contact of male and female parts), or between separate flowers on the same plant (helped by wind or insects). In other words, they mate with themselves. Cross pollination takes place when pollen is transferred from one plant to another plant by insects, birds, or wind. Crossers can’t move pollen without help as the selfers do. Offspring of plants that cross pollinate may have different characteristics than the original variety unless they are isolated from plants of the same species.

Seed packet with description designating F1 seed.

If a package is labeled F1, seeds should not be saved, as they are unlikely to reliably reproduce the same plant as the parent.

A couple of tips on planning a garden for seed saving:

  • Start small and keep it simple.
  • Balance the many factors that comprise the art and practice of seed saving.
  • Begin by choosing a couple of self-pollinating annuals. Peas, beans, tomatoes, and lettuce are easiest to save. Insect- and wind-pollinated annuals may require isolation distances so they don’t cross pollinate.
  • Thoughtfully map out the garden to make efficient use of space. Growing plants for seed may take up more room for a longer period of time. While radish may be harvest-ready after growing 30 days, it may take much longer for your radish crop to produce its seeds.  

Take our classes during the Super Seed Weekend to learn more about planning a garden for seed saving.

Seed savers contribute! Come to learn, swap seeds, and share stories at Super Seed Weekend and experience the satisfaction that comes along with being a seed saver. A broad community of seed savers (new friends) awaits!


©2017 Chicago Botanic Garden and my.chicagobotanic.org

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

Most perennials are deciduous. They go dormant when their above-ground parts die in the fall and then they rely on the energy and nutrient reserves stored in underground roots during the winter. But without a pretty blanket of snow all season, a garden can look drab and dead. Fortunately, there are some perennials with attractive and durable evergreen foliage that last the winter months, even in Chicago.

Why do they stay green so long? Well, evergreen leaves contain lignin, the same polymer in the cell walls of woody plants, throughout the veins and surrounding tissues. This makes them waxy, durable, and less prone to wilt or tear. These leaves are also less likely to get diseases or be browsed by critters. But the main reason for a perennial to have evergreen leaves is to provide a place to store energy and nutrients while they are dormant.

Evergreen perennials are quite trouble free but having modified leaves comes with a price. They are vulnerable to winter burn, a situation where the leaves become dehydrated, leading to injury or death. This can occur in late February or March, when sunlight is directly hitting the plant and the soil is still frozen. The sunlight heats up the leaves and causes them to transpire (lose water), yet the roots remain frozen and unable to replace what was lost. Fortunately, snow cover protects evergreen perennials by shading them and insulating the ground. Also, planting them on the north or east side of a structure will provide ample shade in late winter because the sun is lower.

The energy and nutrient reserves in evergreen leaves are utilized by new growth in spring. This is why most evergreen perennials do not shed their original leaves until the fresh leaves are complete. Older leaves can look shabby by spring, especially after some winter burn, but do resist the urge to cut them off in your garden until this transfer of reserves is complete. Prematurely removing evergreen leaves can weaken the plant and cause them to flower less.

Here are some of the best perennials with evergreen foliage for the Chicago area:

Bergenia cordifolia 'Bressingham White'

Summer: Bergenia cordifolia ‘Bressingham White’

Bergenia cordifolia 'Winter Glut'

Winter: Bergenia cordifolia ‘Winter Glut’

Bergenia, pigsqueak
(Bergenia cordifolia)

Bergenias have 1-foot-tall, leathery, paddle-shaped leaves that turn a mahogany color in the fall and winter. In early spring, clusters of pink flowers are held on thick stems. Blooms are sometimes seen during cooler weather in autumn. Plant bergenias in a partly sunny spot that is moist, but not wet. The common name, pigsqueak, comes from the sound that is made when rubbing a leaf between your fingers.

Helleborus x hybridus 'Blue Metallic Lady'

SPRING: Helleborus × hybridus ‘Blue Metallic Lady’

Helleborus x hybridus 'Solace'

Winter: Helleborus × hybridus ‘Solace’

Hellebore, Lenten rose
(Helleborus × hybridus)

Before the snow has even melted, you will find hellebores in flower. The common name, lenten rose, refers to the ability of this plant to bloom at the beginning of Lent. Green, white, and maroon are the most common flower colors found, and some have attractive spots on the inside. The evergreen foliage is less than 2 feet tall, coarse and leathery, and combines well with ferns and other woodland plants. Rich soil and shaded conditions suit it best and under such situations, self-seeding may occur.

Heuchera 'Carnival Rose Granita'

Heuchera ‘Carnival Rose Granita’

Coral bells
(Heuchera spp. and cvs.)

Coral bells are very popular today, and breeding efforts have led to an overwhelming amount of options to choose from. The maple-like leaves can range from burgundy to black, caramel to red, and chartreuse to silver. Flowers have gotten showier and last much longer too. If afternoon sun is avoided, and the soil is well-drained, they are tough perennials that remain visible all winter long.

Liriope spicata

Liriope spicata is green all summer—and winter—long.

Creeping lilyturf
(Liriope spicata)

Creeping lilyturf is a tough, drought-tolerant groundcover for sun or shade. It spreads by rhizomes and makes a nice alternative to grass, provided you don’t plan to tread on it very much. It also competes well with tree roots. In autumn, the plants produce interesting spikes of violet flowers (sparingly) that lead to black, shiny fruits that look like beads. Variegated cultivars are available too.

Japanese pachysandra
(Pachysandra terminalis)

Japanese pachysandra is an extremely common groundcover for shaded landscapes. It spreads quickly and, once established, remains weed and maintenance free. The glossy dark green foliage is attractive year round, and in spring it boasts fragrant, ivory white flowers. There is also a pachysandra that is native to the Appalachians.  It is called Pachysandra procumbens and it too forms an evergreen groundcover, though much more slowly over time.

Pachysandra terminalis

Spring: Pachysandra terminalis

Barren strawberry
(Waldsteinia ternata)

Barren strawberry is a superb, 2-inch-tall, groundcover for sun or partial shade. The plants are stoloniferous, like strawberries, and spread quickly into a weed-proof mat in well-drained soil. In mid-spring, barren strawberry is loaded with sunny yellow flowers that have five petals each. Hailing from Europe, Japan, and China but a native species, Waldstenia fragaria, has very little difference in habit or growing conditions.

Pachysandra terminalis

Winter: Pachysandra terminalis

Polystichum acrostichoides

Polystichum acrostichoides emerges under melting snow

Christmas fern
(Polystichum acrostichoides)

Native to Chicago and the eastern United States, Christmas fern is one of the few truly evergreen ferns that are effortless to grow. All it needs is some shade and a well-drained spot, and in a few years, you will have a sizable 2-foot-tall plant, forming a 2-foot-wide clump. In spring, cute fuzzy fiddleheads emerge out of the dark former fronds. You can start your own colony of Christmas ferns by digging up mature plants and dividing them into additional ones.

Barren strawberry
(Waldsteinia ternata)

Barren strawberry is a superb, 2-inch-tall, groundcover for sun or partial shade. The plants are stoloniferous, like strawberries, and spread quickly into a weed-proof mat in well-drained soil. In mid-spring, barren strawberry is loaded with sunny yellow flowers that have five petals each. Waldsteinia ternata hails from Europe, Japan, and China. The common name, barren strawberry, is shared with another species, W. fragariodes. The latter is native to the United States; however, nurseries offer it much less frequently than W. ternata.

Waldsteinia ternata

Winter: Waldsteinia ternata

Waldsteinia ternata

Spring: Waldsteinia ternata


©2017 Chicago Botanic Garden and my.chicagobotanic.org