Monday, February 29, 2016

Look For The Meteor Shower (Verbena)!

The weekend was almost balmy with daytime temperatures close to 60 degrees F.  Today is still warmer than usual but the snow arriving tonight and tomorrow will be our "reality check!"  We did have a nice turnout of volunteers though.  Big John, Terry and Larry H. headed out to bring in more elements of the Holiday Light Show (HLS) which is coming down very efficiently.  Most lights and cords are in although John and Terry still have plenty of displays to collect.  Keeping in mind that we expanded the route by 50% this past winter and really bulked up on lights, we're right on track for packing this event away.  Ron R. was out cutting back more grasses while Alan M. helped process cords inside.  Gene and Dr. Gredler were each painting multiple projects.  Dave, Jim, Vern and Ron Y. continued on their carpentry projects which included some repairs as well.  Dick H. made a gas run and helped with some other projects.  Bill O. was in later to help out as well.  We also saw Kathy P. and many others today.

At multiple trial gardens this past summer, I enjoyed seeing a new, compact selection of South American verbena (Verbena bonariensis) called Meteor Shower (see above).  We've grown the standard Verbena bonariensis for many years (photos further below...) and have always enjoyed the profusion of bloom as well as the number of bees and butterflies that will visit this plant.  At 4'-5' in height though, you have to account for that size.  Meteor Shower (PPAF) at only 30" tall, makes for a durable, mid-height selection that has more applicability in containers and in the mid-portion of the sunny border.  Native to Columbia, Brazil, Argentina and Chile, the "straight species" is known for heat and drought tolerance and also deer resistance.  This plant does drop a lot of seed though...However, Meteor Shower is almost seedless and certainly not the problem the taller form can be with thousands of seedlings.  Meteor Shower has not only a more compact height but denser, "lollipops" of lilac blooms that are quite clustered.  This selection is offered as a plant (vegetatively grown) and while I still see value in the taller form, Meteor Shower has a bright future and should be included in any garden for pollinators!

 Verbena bonariensis  Meteor Shower (PPAF)
 Verbena bonariensis  Meteor Shower (PPAF)
 Verbena bonariensis  Meteor Shower (PPAF)
Verbena bonariensis  Meteor Shower (PPAF)
directly above and all the photos below are of the standard Verbena bonariensis

 Photo above and below from Ken Tapp

Friday, February 26, 2016

'Henry Eilers' Sweet Coneflower

One of my favorite, taller perennials for full sun is the 'Henry Eilers' sweet coneflower (Rudbeckia subtomentosa) seen in all of these photos.  This selection of the native species differs in that it has "quilled" petals that are rolled over and fused...creating a "tubular" look to these pinwheel shaped, 3" wide blooms.  Sweet coneflower is a native plant, hardy to zone 4, that thrives in full sun and shrugs off our hot and humid summers.  Exhibiting drought tolerance as well as adaptability in clay, this tall perennial adds color for over two months from late July until mid September.  Normally the flower petals are flat but this unique selection was found by Henry Eilers, a well known horticulturist and retired nurseryman, in Southern Illinois along a prairie remnant adjacent to a railroad.  This varietal selection was introduced in 2003 by Larry Lowman.  Rudbeckia subtomentosa 'Henry Eilers' will typically reach heights of 5' and taller and we've seen it get 7' or so during years with ample moisture.   Incidentally the "sweet" reference in the common name had no relation to the flowers but to the foliage which smells lightly of vanilla when rubbed or bruised.  Seedlings are not reliably like the parent plant so spring division is recommended for consistency in appearance.  While I feel there is ample opportunity for this plant in the back of a full sun border, there is now a variety called 'Little Henry' that has the same look but on a more compact plant that tops out at 36" in height.  Both selections will attract butterflies and are also commonly used in a naturalistic plantings and rain gardens. 

The weather continues to be fine for outdoor work with temperatures in the mid 30 degrees F and overcast skies.  Big John continued processing Holiday Light Show (HLS) supplies for storage.  Bill O. came in to organize some of the items we are currently painting for a fresh look this year.  Vern worked on a carpentry project.  We also saw Jim H., Mark S., Dr. Gredler and many others today.  I ordered some more seeds and am almost done with that process. I'm moving on shortly to our perennial and woody plant orders and continued preparations for the myriad events and educational opportunities here at the gardens.  I always when people ask if winter is my "down time"!  Last night we had a nice turnout of 37 attendees at the second of our eleven monthly Lecture Series topics; New Plants.  The next topic is Emphasizing Foliage in the Garden on Tuesday, March 29th at 6:30 pm ($3 for RBG Members and $5 for non-members).

 the grass in the foreground (above and below) is 'Sioux Blue' Indian grass (Sorghastrum nutans) - perennial

Thursday, February 25, 2016

Cool Cardoon (Cynara cardunculus)

We had another relatively mild day with temperatures well about freezing.  Big John and Larry continued work on the continued take down of the Holiday Light Show (HLS).  Marv B. later helped out with this process.  Ron P. continued repairing lights and both Alan and Ron R. headed out to start cutting back some of our ornamental grasses.  Alan also swept and helped with the HLS.  The cooler season grasses may start actively growing in March if we get more warm weather which makes this cutting vital right now.  We still have plenty of tidying to accomplish out in the gardens and I want everything looking nice for our March 19th Spring Symposium (Plantaholics Retreat).  We still have plenty of room at this event which should be a blast.  See information on the program and registration details at  Vern, Dave and Jim continued on some carpentry projects and Dr. Gredler continues to be our main painter and had plenty of work today.  Dick H. was working on some of our mowers and Kathy came in to help out with some office work.  Gary continued making plant labels for some of our spring orders.  Bill O. came in later to help wrap up cords from the HLS  We also saw Rollie and many others today.

I think we've grown cardoon (Cynara cardunculus) every year at RBG as an annual (hardy to zone 7).  In short, I love the rugged, silvery contribution out in the garden from this plant.  The imposing architecture of this plant is impressive and silver can be excellent in the garden (see cardoon with "backlighting" above).  Native to portions of the Mediterranean and Europe, this member of the sunflower family has a long history of cultivation as an ornamental plant and an edible.  The celery-like stalks may be harvested, blanched, steamed or braised...then eaten.  Blanching (excluding sunlight) tenderizes and improves stalk flavor.  Introduced to North America in the mid 1800s, this plant will get 4' tall and 4' wide during our warm growing season (larger in warmer climates).  This plant is considered invasive in California and has naturalized in other warmer climates.  The close cousin to cardoon is the artichoke which has a similar look but is used in a different fashion.  We plant cardoon in full sun in nice soils. Providing ample watering and continuing to remove the oldest leaves on the outside of the plant as they arch downwards makes for a happy plant.  We have seen some mildew problems on occasion and unfortunately, aphids seem to enjoy them as well and can be found in profusion on the underside of the leaves. Slug damage is occasional too.  Regardless, the strong architectural contribution of this silver plant is excellent in the garden and the "real estate" dedicated to cardoons brings back a strong "visual return"!

Cynara cardunculus at Olbrich Botanical Gardens (Madison, WI) above and below

nice use of Cynara cardunculus at Allen Centennial Gardens (UW-Madison) above

 showy blooms of cardoon (above and below) - they necessarily bloom each year though...

 light frost on cardoon (above)
 cardoon and bronze fennel (above)
 'Porto Spineless' cardoon (Cynara cardunculus) above and below

Wednesday, February 24, 2016

Mukdenia 'Karasuba' (Crimson Fans)

I've enjoyed growing this perennial for many years and photos like the one above will make any gardener appreciate the value of the late season coloration on these fanned, maple-like leaves of mukdenia (Mukdenia rossii 'Karasuba').  This coral bells (Heuchera) relative is native to rocky slopes and ravines in China, Manchuria and Korea.  Preferring moist, fertile and well-drained soils, this hardy perennial (to Z4) blooms in early spring (see below) and the foliage starts with red pigmentation on the leaf tips in summer with an increasing degree of red until frost.  It is important to note that the variety 'Karasuba' is identical to 'Crimson Fans'.  Reaching 16" or so in height and ultimately 24" in width, this plant has thrived for us in part sun which it seems to prefer.  Ample moisture is again important but the ornamental merit of this plant is quite evident in both Spring and Fall.  It is important to note that these first three photos (taken at the Walters Gardens Trial Garden in Zeeland, MI) are the best shots I've taken of this perennial later in the season.  The degree of red seems to vary each year and those with more sun seem to have stronger coloration.  Regardless, this perennial has a bright future in our partly shaded garden!

As I type this blog, the Chicago area is getting pounded with snow but we were spared from this recent system.  The cloudy day, while cool, still allowed for lots of progress out in the gardens with the take down of the massive Holiday Light Show (HLS).  Both Larry H. and Big John headed right out to continue retrieving many of the lights, cords, luminaries and other elements of the show that had been trapped in ice for the last six weeks.  Myrt and Gena came in for some painting today.  Janice was in to work on research for the Spring Plant Sale.  We also saw Cindy, Bill O., Dick H. and our Horticultural Therapy Committee (Cindy, Darcie, Janice, Art and Karen) was at the Horticulture Center for their monthly meeting.  We continue to plan for our July 27th Horticultural Therapy Symposium (more details to follow).  I continue to prepare for Spring out in the gardens as well as our Spring events like the Compost Sale and Spring Plant Sale.  We do have some early bulbs up in the gardens (snowdrops and winter aconite) which I'll photograph soon.  Spring is in the air!

emergence in early May (all bloom photos taken in late April or early May)