The Horticulture Blog
About the HORTICULTURE BLOG
Liz Vogel, our staff horticulturist writes articles on seasonal plantings and landscaping at the park district, along with some tips to try in your home garden.
Do you have a gardening question for Liz? Email it to news@DPParks.org.
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About Liz Vogel
Liz earned her Professional Gardener and Garden Design Certifications from the Chicago Botanic Garden, and furthered her education by receiving her Masters in Landscape Architecture from the University of Illinois. Through the design and implementation of projects large and small, Liz continues to grow her understanding of plants and nature, and enjoys sharing what she has learned with others. Her column, “From the Ground Up,” can be seen each month in the Journal & Topics newspapers.
Liz has developed a series of classes for kids ages 6–8, 9–11, and everyone 12 and older. Take these classes with Liz and her expert team of gardening gurus and watch your garden grow as never before! Read about them here.
THE HORTICULTURE BLOG: The Dormant Season
By horticulturist Liz Vogel.
This is a quiet time in the garden for most — though there are some things that can be done to keep our minds entertained, and that will allow us a feeling of connectedness to the other side when it feels that the cold will never end.
Now until late winter is a great time to sow native plant seeds. You can do this outdoors as long as you can see the ground and are able to loosen the soil just a bit to create furrows where the seed can settle. I generally follow this with a sprinkling of soil lightly tamped to create a good seed/soil connection. When the ground is covered in snow and frozen solid, it is best to wait until a warm sunny day in late February when the dark coatings of the seed will collect just enough heat to melt a pathway through the snow and deliver it to the moistened soil below.
Plants native to Illinois are brilliant, knowing just when conditions are right to emerge. Some seeds of these plants have hardened coverings that require several seasons before moisture is able to breach the protective coating, others need cold followed by warmer temperatures for a specific number of days. Others need a cold dry environment, exposure to sunlight, or to be buried just below the surface (or some combination), to signal that it is safe to sprout. If you are interested in growing some species at home, you can cheat a bit by attempting to duplicate these outdoor conditions.
Seeds from the pea family (Fabaceae), such as Baptisia australis (false blue indigo), Cercis canadensis (eastern redbud), Amorpha canescens (lead plant) have a hard coating that can be lightly scratched (scarified) with sandpaper to help allow water in. I use a drywall sanding block atop a fine grit sheet of sandpaper, rubbing the seeds in a circular motion until a powdery residue is left behind. Follow this scarification treatment with a couple of weeks or more wrapped in a damp paper towel within an airtight container in the back of the refrigerator (a method of treatment called cold/moist stratification).
Many native species need some form of stratification for periods ranging from 30 to 90 days. These include Ruellia humilis (wild petunia), Penstemon digitalis (foxglove beardtongue), Coreopsis lanceolate (lance-leaf coreopsis), among others. And some require very little at all to get growing — just a bit of warmth and consistent spring rains. Monarda fistulosa (bee balm), the familiar Echinacea purpurea (purple coneflower), and warm season native grasses fall into this category. These no-stratification-needed species can be sprinkled over loosened bare soil outdoors through late June.
As for me, I will begin seed treatments soon for sowing and germinating February through April in the Park District Greenhouse. We will be growing from seed collected this fall in our district gardens, along with some new and unusual additions. You can start your seed indoors as well, keeping them in a sunny window until transplanting in the garden mid-spring.
If you are interested in learning more about germinating and growing native plants and would like to volunteer in our Greenhouse this growing season, please email me at firstname.lastname@example.org.
Cercis Canadensis (eastern redbud) at Arndt Park in Des Plaines, with attached seed pods.
Cercis Canadensis (eastern redbud) seeds that will be pre-treated before sowing.
THE HORTICULTURE BLOG: Where are they now?
By horticulturist Liz Vogel.
Praying mantis egg case attached to the stem of Calamintha nepeta within the foundation garden at Prairie Lakes Park. (Photo by Liz.)
WHERE ARE THEY NOW
Of all the disciplines and practices that I like to claim – artist, designer, gardener – I think most of all I am an observer within the small parcels that I tend.
On a late fall day, when the temps have settled in the lower portion of the thermometer and mornings bring a stunning display of frost lined leaves and stems, I think about all of the usual garden suspects and wonder where they are now. Gone are some birds, butterflies, and dragonflies who follow the Lake Michigan flight path south and mingle over-head come late August, September and October.
Those still in the garden though, in some form or stage, are the caterpillars of the endangered pearl crescent butterfly who overwinter under the basal leaves of some asters such as the big-leaved and sky-blue varieties. The black swallowtail butterfly overwinters as a chrysalis, delicately tethered to the side of a dried branch or stem. The Queen bumblebee is tucked away in the soil or under dried leaves, having produced an anti-freeze-like chemical to withstand the coming cold. She will emerge early in spring to search for a new nesting location.
Who else is still in the garden? The praying mantis, in its smallest form wrapped up in a sandy brown case among hundreds of other fertilized eggs. You may see these structures in the garden, attached around a small tree branch or sturdy stem, and witness as the nymphs hatch mid-spring. They look like a band of tiny aliens patrolling the area.
Among those that find shelter within craggy bark or small holes in a tree? The mourning cloak and comma butterflies, along with a variety of beetles and small native bees.
My point in all of this is that though it is cold and quiet, and possibly covered in snow, many of our summer favorites are still in the garden – as egg, caterpillar, chrysalis or adult – waiting for warmer temperatures to return before they once again buzz and weave among our flowers.
We can all help them out by being a bit less tidy and allowing fallen branches, dried leaves and old plant stems to remain. When cutting back (no matter what time of year) clip dried stems into smaller pieces and tuck them between upright branches to help hold them during windy days. Then step back and take in the beauty and growing complexity of your nature-focused garden.
THE HORTICULTURE BLOG: Winding Down
By horticulturist Liz Vogel. (Photos by Liz.)
Echinacea pallida (pale purple coneflower) mature seed heads – a fall favorite.
After spending all season training your eye to spot the outlier within your garden beds, and working to tidy up unwanted species that have wandered in, it may be time to dial back the need for clean. As the majority of plant growth is put on pause for year, take this opportunity to step back for a good look at your garden and make some choices for the coming year. First up, we must decide what to do with the current fading flowers, stems and leaves: my advice is to be selective. While even I cannot help myself from cutting back the gnarly grey stems of Salvia, whose glowing purple spires are all but a distant memory, other plants like Echinaceahave parts that provide great function if left in place (or partially in place) over winter and into the following year. Two common species of Echinacea are E. purpurea (purple coneflower) and E. pallida (pale purple coneflower); both appear to provide just as much function after flower as they do while in full bloom. They have large hollow pithy stems that if cut to a height of 18” or more become potential nesting for native bees, and the flowers mature into dark orbs packed full of large seeds that attract the very charismatic American goldfinch. If you have a large stand of Echinacea, you will likely know these chattery fall visitors who stop by as they migrate south for the winter. Leave the seed heads in place until at least early November, and until spring if this fits into your garden stewardship schedule.
Grasses such as Sprobolus heterolepis (prairie dropseed) or Schizachyrium scoparium (little bluestem) develop beautiful golden tones with seed heads that sway in the late season winds. These grasses (among others) provide food and nesting for small birds and other animals, so if you are ok with hosting this bit of wildlife, leave the grasses in place until late winter clean-up, at which time you can steady the hedge trimmer, shears or pruners and chop them back to about 6”.
Some tips for fall garden clean-up
–To prevent re-seeding of some of the more successful plant species such as native Symphyotrichum spp. (asters) in your beds, cut mature seed heads (post flower) before the wind and rain help to disperse them.
–To get a jump on next year’s cleaning, go ahead and cut back some plants now if you like. Select those that offer limited environmental and aesthetic reward through winter. These may include Salvia nemorosa, Alliumcultivars such as ‘Summer Beauty’ and Coreopsis verticillata among others. “Chop and drop” to a desired height, and allow the dried stems to lay in place as natural mulch. Leave plants with striking seed heads, and then cut those with hollow stems—such as Echinacea (purple coneflower), Rudbeckia (black-eyed susan), Monarda (bee-balm), Eutrochium (joe pye weed)—to 18” late winter to provide summer nesting opportunities for native bees.
Leave the leaves!
There is so much happening in the fallen leaves that collect in the garden: Beneficial insects overwinter in this debris, and many organisms feed on this matter as they help to build heathy garden soil. No matter what your gardening practices are, make sure your garden looks good to you (and your neighbors) and try to squeeze in some added environmental benefits whenever possible.
Prairie Lakes foundation garden with Salvia cut to 10”; Echinacea and Agastache will remain until spring. (Photo by Liz.)
THE HORTICULTURE BLOG: Fall Colors and Textures
By horticulturist Liz Vogel.
In the butterfly garden at ALC, dark orbs of the Echinacea pallida (pale purple coneflower) stand out against a backdrop of Solidago nemoralis (old field goldenrod) and Symphyotrichum oblongifolium (aromatic aster) that is just starting to bloom. (Photo by Liz.)
FALL COLORS AND TEXTURES
For many gardeners the first signs of fall in the garden bring a mix of emotions –a look forward to the marvelous array of colors and textures that will soon be on full display, and a signal that another gardening season is coming to a close. If you look closely at the goldenrods in the next few weeks you will see an insect bonanza –all shapes and sizes coming together to feast on the last flowers of the season and their abundant pollen and nectar. Asters serve a similar purpose drawing late season butterflies and many bee species to buzz pollinate their way around the disc florets at the center of each flower –this is really fun to watch! Here at Des Plaines Park District, we have begun collecting seeds from the Baptisia, Penstemon, Echinacea, Coreopsis and others that we will clean, store and stratify to be ready for germinating late winter and early spring –there will be many more to gather before the heavy rain and winds of fall do their thing. So, while the garden prepares to sleep, we will take in the sounds and smells of a hard fought season, and we will marvel at all we have been lucky to see.
If you are looking to up your late season spectacle, these are some of our favorites:
Asters Symphyotrichum spp. – in many shapes and sizes!
Grasses such as Sporobolus heterolepis (prairie dropseed), Schizachrium scoparium (little bluestem) and Bouteloua curtipendula (side-oats grama). We love plants with striking seed heads such as Ascelpias spp. (milkweed), Echinacea pallida (pale purple coneflower), Baptisia australis (false blue indigo), Monarda fistulosa (bee balm), Dalea purpurea (purple prairie clover), Parthenium integrifolium (wild quinine), and Penstemon digitalis (foxglove beardtongue) among others.
If you see us out in the gardens, stop to say hello and let us know what you are growing (or collecting).
Fall is seed season, and the pods from many plants add a wonderful texture to the garden. Pictured here is Asclepias tuberosa (butterfly weed) with upright pods which will soon ripen to release small tear-shaped seeds attached to filaments for wind dispersal. The finer textured Asclepias verticillata (whorled milkweed) flowers late in the season and adds a softer hue to the composition. (Photo by Liz.)
THE HORTICULTURE BLOG: On Butterflies
By horticulturist Liz Vogel.
While out tending the newly planted natives garden at Chippewa Park recently, I had a wonderful conversation on butterflies and what they eat (along with water pumps and large trucks).
As adults, butterflies visit many flowers to drink nectar, but in the larval stage (as caterpillars) they are very specific foragers and many rely on a particular plant family or genus to feed until they are ready to undergo metamorphosis. Some of these special relationships include Asclepias (milkweed) and monarch butterflies, plants in the carrot family (such as Zizia (golden alexanders) and black swallowtail butterflies, Ruellia (wild petunia) and common buckeye butterfly, and Symphyotrichum (asters) and the endangered pearl crescent butterfly. These are all great plants for your home garden and not only will you get beautiful flowers, but you should see plenty of butterflies.
Thanks for stopping to chat today Finnegan – keep an eye out for those caterpillars!
If you see me out in the gardens, please stop to say hi and share with me what you have been planting!
THE HORTICULTURE BLOG: Drought Tolerant Natives
Third in the series by horticulturist Liz Vogel.
Baptisia spp. cultivar at the park district Greenhouse on Maple Street. (Photo by Liz)
This spring started with unusually hot and dry conditions, which had our landscape crew running quite a bit to keep all of our new plantings watered and happy until they began to settle in. Fluctuations in temperature and moisture are nothing new here in Illinois, and many plants have evolved nicely to accommodate these rather dramatic swings. Roots systems of some native plants, such as Panicum virgatum (switch grass))— a mid-size grass that fits well in larger gardens or as a backdrop to smaller species—can reach 10–15’ into the soil. Though we marvel at much of what is happening above ground with colors, textures, and flowers that attract a host of insects and birds, some of the real work is being done below the surface where large root systems work to cycle water and mine for nutrients. The regeneration (dead organic material in the soil) is what feeds microfauna and helps to create healthy soil.
As you plan your new garden and garden additions, give some thought to integrating these and other drought tolerant grasses and wildflowers into your landscape. Until next time—keep gardening! Liz.
Schizachyrium scoparium (little bluestem)
Sporobolus heterolepis (prairie dropseed)
Carex pensylvanica (pennsylvania sedge)
Asclepias tuberosa (butterfly weed)
Baptisia australis (blue wild indigo)
Ruellia humilis (wild petunia)
Echinacea pallida (pale purple coneflower)
Liatris punctate (dotted blazing star)
Symphyotrichum sericeum (silky aster)
A deeper dig into soil life and structure:
US Botanic Garden Exposes Secret Life of Roots:
THE HORTICULTURE BLOG: How Bees See
Second in the series by horticulturist Liz Vogel.
Photo by Liz.
Among the spring flowers growing in the park district gardens is the lovely native Phlox divaricata or wild blue phlox. This plant, along with Anemone cylindrical, Zizea aurea, Allium spp. and other early wildflowers, picks up where the redbud trees, seasonal tulip, and daffodils leave off. Blues and purples are common among native spring flowers, and the bees that forage among them use the unique markings at the center of many flowers as a type of runway or beacon–pointing to where the sweet nectar reward of each flower is stored. Many bees come out early in spring, even before we start to see butterflies. Because bees see mostly in blue, green, and UV light, they can easily pick up on these colors and markings as they buzz by the flowers moving in the wind. (Photos by Liz.)
For more on how bees see, visit these websites:
For more info on native vs. cultivars in the garden:
THE HORTICULTURE BLOG: Spring Pollinators
First in the series by horticulturist Liz Vogel.
Photo of an Adrena Bee on a Willow, by Liz.
Spring is a very important time of year for pollinators. Small native mining and cellophane bees—both of which are quite small, solitary, and live in the ground—are some of the first to emerge on a warm sunny day to forage among the early spring flowers. The park district is introducing many native flowering species to our garden beds, and those will help feed these bees and many other tiny visitors.
Here are just a few of the wonderful native spring flowers that might work well in your home landscape: Dodecatheon amethystinum (Amethyst Shooting Star), Geranium maculatum (Wild Geranium), Hepatica acutiloba (Sharp-lobed Hepatica), and Polemonium reptans (Jacob’s Ladder).
We’ll be bringing you more information about our horticultural activities across the district every month via social media. If you have questions, be sure to post them here. We’ll respond as soon as we can, which might take a day or so during this busy planting season. Happy gardening!