Cedar Valley Arboretum & Botanic Gardens

Archive for November 2009


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It’s that time of year again when we brace ourselves for the snow and dropping temperatures.  The leaves have fallen, gardens are put to bed and there’s nothing left to do but wait.  At least that’s the doomsday attitude that sneaks up on me every once in awhile!  But actually, there is still plenty to see in the gardens.  It just takes a keener eye and an appreciation of our garden’s life cycles.


Do you have family in town for Thanksgiving?  I encourage you to walk of that “turkey coma” at The Arboretum!  The red and yellow-twigged Dogwood are striking in the Arrival Gardens and there are several succulents (Itty-bitty … you’ll have to look close!) adding texture and subtle color to the beds just outside the Education Center.  And if you come late afternoon when the sun is low in the sky, the leaves on the weeping willow look just like golden drops falling from the sky.


Happy Holidays to you and yours.  See you in the gardens.


Written by cedarvalleyarboretum

November 24, 2009 at 8:00 am

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Really. Big. Rabbits.

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As you can see, we take our rabbit fencing seriously at The Arboretum!  The bottom of the arborvitae are bare from previous year’s damage and new growth is just now returning – we aren’t willing to risk it again!  The fencing is especially tall on the north side after last year’s snow drifts made it quite easy for the rabbits to hop over the shorter fence!  (Thank you to the “Maintenance Men” who worked so diligently on this project!)


Have you done any critter proofing at your house for the winter?  Unfortunately, it seems like their tastes change from year to year so it’s hard to know what they will go after.  I suggest fencing small ornamental trees and susceptible shrubs.  The rabbits seem to especially like burning bushes at The Arboretum, as well as our small fruit trees and ornamental conifers.


You might also consider wrapping the tree bases of your younger trees.  Small caliper and thin barked trees are susceptible to sun scald.  Damage occurs when the bark heats up on sunny days and the tree breaks dormancy.  When the tree bark cools down, the tissue dies, leaving a crack or sunken spot in the bark.  Wrapping the tree ensures more consistent temperatures on the bark.  Place the wrap on the trees in the fall and remove in the spring after last frost.


See you in the gardens.

Written by cedarvalleyarboretum

November 19, 2009 at 10:22 pm

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Winter Sojourn

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Picture 004I was just reading online where one gardener described the months ahead as our “winter sojourn.”  This is much nicer than my mom’s description of winter as the “vortex of terror!”  I’ll try to keep an upbeat attitude for now, but it seems as we get closer and closer to spring, our hibernation seems more and more like a terror! 


Is your garden all put to bed?  Any last chores to do?   I still have cannas to dig at The Arboretum.


Cannas are grown (and loved) in Iowa for the splashy, tropical feel they bring to garden and patio containers.  The broad leaves vary in color from dark green to red to maroon with many variegations in between.  The flowers are usually red, yellow or orange.


Cannas grow from rhizomes, a horizontal stem of a plant grown underground with roots and shoots.  (Harvested ginger is a rhizome.)  Since cannas cannot overwinter in Iowa, we must lift these rhizomes each fall and overwinter indoors.  Plants with fleshy storage structures like this (also include bulbs, corms, tubers and roots) are called “tender bulbs.”


Interesting fact: Canna rhizomes are an excellent source of starch for humans and livestock and were once a staple food product in parts of the world.


So how do you overwinter cannas?  After the first frost, cut back the foliage to a few inches above the soil.  Using a pitchfork or shovel, lift the rhizomes out of the soil being sure to dig out far enough as to not pierce the rhizome.


There are differing opinions on cleaning and storage, and really, depends on how much effort you are willing to put into your cannas.  I have had good luck shaking off extra soil from the rhizomes and throwing them in a cardboard box in the basement.  Other years I have done a more thorough cleaning job and then let them dry out for a few days in the garage before storing for the winter.  I layered the rhizomes in a box with newspaper (you could use peat moss, wood shavings or similar material).


The technique can vary, but a few points to keep in mind:

  • Cool temperatures, but not freezing.  Ideal temperatures are between 50 and 60 degrees.  The rhizomes can start to deteriorate lower than 45 degrees.
  • Moisture.  A bit of moisture goes a long way in keeping the rhizomes from drying out, but too much creates an environment for rotting.
  • Air circulation.  A bit of air movement will also help in the rhizomes from not rotting.


After chances of frost have passed for the spring, again plant your canna outdoors.  Healthy rhizomes will be firm to the touch.  Throw away any rhizomes that are soft or mushy.  And remember, no overwintering technique is foolproof.  If you do not have success, don’t be afraid try again the next year!


See you in the gardens.

Written by cedarvalleyarboretum

November 16, 2009 at 6:01 pm

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A Closer Look

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Picture 011

We are seeing the transition from users to stewards throughout our nation, with the popularity of reusable grocery bags and water bottles, chemical-free produce and discussions of carbon footprints.  The idea of land stewardship is also (thankfully!) following us into the garden.  We’re seeing more sustainable practices like choosing site-appropriate plant material, water conservation and going the route of organic instead of harsh chemicals.  These are excellent practices and should be done by all gardeners, whether it is be a few pots on a balcony, foundation plantings, a vegetable garden or large perennial beds.


But I think as gardeners, we can also take this refound people-plant connection to another level.  And while a base of horticulture knowledge can be helpful, it’s not as necessary.  It is more about critical thinking, a sense of curiosity and sometimes, a bit of patience. 


To explain this thought shift, I thought we would use ornamental grasses as our example.  Ornamental grasses have definitely taken the spotlight over the past few years and the term “ornamental grasses” is so popular now that it doesn’t even need explanation, when only a few decades ago it would have.


So we are standing in our garden or home landscape and decide we would like to incorporate some ornamental grasses.  Initial reaction might be to stop by our local nursery to pick up a few varieties that catch our eye, take them home to plop in the ground and you’re done.  That could work, but I think we can do better than that.  And if we take a few quick and easy steps at the beginning, we’ll see the reward as our garden develops and takes shape.


There are four steps we should take before purchasing our plant material.

Do your research.

Consider your design.

Understand your limitations.

Consider plant communities and seasonal appeal.


Do your research.  What do we know about ornamental grasses, on the surface?  How have the nurseries and garden publications marketed ornamental grasses to the public?  They are low maintenance, drought tolerant and native to our area.


But before purchasing, it would be helpful to know a little bit more.  This is where that critical thinking comes in.  Luckily with today’s technology we have information at our fingertips.  So we can go online or pick up a gardening book and find a bit of background information about ornamental grasses.  Inside the Poaceae family, there are thousands and thousands of species and among the species categorized as “ornamental grasses,” there even still a huge variety.  But instead of feeling overwhelmed, this should be freeing!  There is no way to know it all, which takes the anxiety out of it. 


 So we start small and try to identify some basic differences between the popular varieties of ornamental grasses.

Miscanthus (Maiden Grass).  Very popular genus with common clump- forming habit and dense seed head, but also great variety of blade shape, size and color and overall plant size.

Molinia (Moore Grass).  Sturdy stems hold seed heads above arching tufts of green foliage.

Schizachyrium (Little Bluestem).  Dense, fine-textured foliage with seed tufts along each stem.

Sporobolus (Praire Dropseed).  Open, branching seed heads on slender stems that rise above clumps of arching foliage.

Calamagrostis (Karl Foerester Grass).  Upright golden spikes with dense, green foliage.


Consider design.  After we can recognize the difference in our plant material, choosing for our design becomes much easier.  Variables we want to consider are size, growth habit/form, color and texture.  So instead of knowing the specific plant, you can make a checklist of requirements.

For example, we want a grass with a fine texture that provides airy movement in the garden.  Molinia provides height and transparency while Sporobolus provides transparency similar to Molinia, but does so with less height.  Or perhaps you want to make a dense screen with dramatic seed heads.  Miscanthus would be an excellent choice and comes in a variety of heights.  You would also have the opportunity to play around with color as well as texture.


Understand your limitations.  This somewhat goes hand in hand with your design in respect to size and form.  But you also need to consider light, moisture and soil quality.  Most ornamental grasses cannot grow in shade – just a fact, and no getting around it.  Cutting down trees to get sun is most likely not worth it, but some variables can be amended.  For example, you could incorporate organic material to a clay soil to improve drainage.  You also want to consider the long-term growth of your chosen plant – does the grass you chose stay in a clump or spread?   In a naturalizing bed, spreading might be more acceptable while in many small spaces it would not.


Consider plant communities and seasonal appeal.  How will your chosen plant material interact with its neighboring plants?  Ornamental grass can be an excellent focal point or also take up negative space – provide backbone to the garden.  The appeal of ornamental grass is also its four-season interest.  When many plants are turning in for the year, ornamental grasses are at their height, and many are strong enough to stand all winter.


Purchase your plant material.  And finally, you’re ready to purchase your plant material!


The great thing about gardening is that hard work almost always reaps reward and always worth the extra effort of thoughtful design and planting.  There is a sense of bonding over shared workload and pride, and great opportunity for creativity and personal taste.  Gardens can be a source of meals, site for friendly gatherings, and more than anything a happy place for you and yours.  I hope you will take time to consider your plant connection the next time you work in your garden or visit other landscapes.


See you in the gardens.

Written by cedarvalleyarboretum

November 5, 2009 at 7:24 pm

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