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Q & A with Ruth Clausen, Co-Author of "Essential Perennials"

by Shelley Pierce October 18, 2015

Q & A with Ruth Clausen, Co-Author of “Essential Perennials”

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Ruth Rogers Clausen, a horticulturist trained in England, has been living and working in the United States for many years. Over her long career she has taught and lectured widely. Former horticulture editor for Country Living Gardener, she has written several books, including Perennials for American Gardens, co-authored with the late Nicolas H. Ekstrom. Others include Dreamscaping and 50 Beautiful Deer-Resistant Plants.


Read on for information about Ruth’s latest release Essential Perennials and find out how to win a copy of her book, courtesy of The Timber Press!

Your book features 2,700 perennials in full color.  What goes into making a resource of this magnitude and how long of an undertaking was it?  What inspired you to take this on?

Both Thomas Christopher and I have been fascinated with perennials for many years. Earlier, I co-authored Perennials for American Gardens (with Nicolas Ekstrom) that is now out of date and out of print, but did extremely well. Obviously there was a great interest in growing perennials in residential gardens and Timber Press and we were delighted to try to satisfy it. It took us about 30 months to complete, with extensive research, our own experience in gardens across the country, and a great collaboration with Linda and Alan Detrich who shot the amazing photographs.


If you had a bucket list of perennials that you have yet to see or experience firsthand, what would be some of the perennials on that list?

I would like to be able to grow some perennials that are not hardy in my Zone 7 garden. Californian native Matilija poppy (Romneya coulteri) comes to mind.  Blue poppy (Meconopsis betonicifolia) is another I have seen blooming its head off in Canada, but summer is far too hot and humid for it in Maryland. Madeiran marsh orchid (Dactylorhiza foliosa) is a favorite I saw thriving in Engand, but have yet to be successful with here; native showy ladyslipper (Cypripedium reginae) is another orchid I would like to grow.  The bucket is just starting to fill up!


What are the top 5 essential perennials that no gardener can do without?

This would vary according to the climate of course. Florida gardeners would have a different “essential” list from those in the Midwest. However, generally speaking I would suggest: Lady’s mantle (Alchemilla mollis), astilbes (Astilbe x arendsii) and hostas (Hosta, unless you have deer) in shade, native sneezeweed or Helen’s flower (Helenium species), hardy geraniums (Geranium species), especially ‘Rozanne’ for bloom and bigroot geranium (G. macrorrhizum) for a groundcover in light shade. Too bad I am restricted to just 5!


With the thousands upon thousands of perennials in existence, you must have had to make some tough choices on what to include in your book.  How did you decide what made the cut and what didn’t?

Yes, it was quite difficult. From the beginning we decided to exclude grasses and ferns as these huge groups should stand alone. Initially we listed perennials we had grown and liked (both Tom and I have gardened in various parts of the country), looked at what is on the market, and we consulted the literature. We also selected plants that did well in various climates and conditions. For example, we wanted to include a wide range of plants for different locations: for sunny places, shaded spots, dry soil and damp soils. We were also concerned about including plants that flourished with average care; we were careful to include notes in the text regarding particular problems for particular plants. Our editor Tom Fischer made the final cuts and we were pleased that he did so.


With the overwhelming selection of perennials to choose from, what advice do you have for gardeners on narrowing the choices down?

Realistically many of us are impulse plant buyers, and then worry about where a new plant will go! But all these factors and more listed below should be part of planning your perennial garden. However, at the end of the day what really matters is that you are happy with the process and the results.

My advice is:

  1. Look at your surroundings, hardiness zone, and climate. If you are unsure check with your Cooperative Extension office. Each state has one connected to its Land Grant University (eg. Cornell Univ. in NY, University of Maryland in MD).
  2. Have your soil checked for its fertility. The results will tell you what fertilizers to apply for optimum growth; some plants prefer acid soil, others like a sweet soil with lime included. Cooperative Extension offices usually have facilities for soil testing at low cost.
  3. What perennials do you like? Check your neighbors gardens, visit public gardens in your area, attend their educational talks, visit local independent garden centers and nurseries where you can get advice from plant people.
  4. Narrow your list down to plants that obviously do well in your area. Do a little research online to determine the best growing conditions for those particular plants.
  5. It’s usually best to make a drawing of your garden and mark in which plants you would like to grow. If you are away all summer it is unlikely that you will want to have a glorious garden in your absence. In that case concentrate on plants that will give you a fine display in spring and fall.


How is your book different than the other books on perennials at our local bookstore?

I think our book stands out from many others because it is reader-friendly, written from longtime, wide experience cultivating perennials in different parts of the country. For example, we paid particular attention and noted plants that tolerate or do not drought well, that are generally deer resistant or not, and that thrive or “melt down” in summer heat and humidity. The book includes many of the best garden-worthy native perennials, along with plants from other parts of the world (exotics). Combining plants is important, especially to new gardeners and so we suggested other perennials as companions.  In addition Essential Perennials is superbly illustrated. We took the time to select the best photographs to make this volume attractive as well as educational.


To enter, simply leave a comment on this blog post by midnight on Thursday, October 22, 2015 (be sure to provide a valid e-mail address) in answer to the following question:

What is your favorite perennial?

Be sure to include a valid e-mail address. The winner will be drawn at random from all qualified entrants, and notified via e-mail. (See Rules for more information.)

UPDATE 10/26/2015: Congratulations to Cindy Peterson, the winner of the Essential Perennials giveaway!

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45 person already talking about this.
    Rajee Pandi
    Comment added October 23, 2015Reply

    Mums are my favorite

    Kathryn C
    Comment added October 22, 2015Reply

    my favorite perennials are Clematis vines- really any color! I have a purple one in my yard & would love to get other colors


    Julie Peck
    Comment added October 22, 2015Reply

    Peonies and coneflowers

    Anandi A Premlall
    Comment added October 22, 2015Reply

    I love Rosemary! The way my hands smell when I'm pruning them, the way they look like tiny Christmas trees, and their the herbal properties.

    karen d
    Comment added October 22, 2015Reply

    peonies are my favourite

    Comment added October 22, 2015Reply

    Since I can't grow lemon trees where I live, but I love the scent of lemon, I'll choose lemon balm.

    Jason Steinmetz
    Comment added October 22, 2015Reply

    Mums by far

    Melissa Tippie
    Comment added October 22, 2015Reply

    What is your favorite perennial? Calla Lilies are my most favorite perennial! I so love pretty flowers. :-) Thank-you for a great #giveaway!

    Cindy Peterson
    Comment added October 22, 2015Reply

    I love my tulips in the spring.

    Comment added October 22, 2015Reply


    philip halter
    Comment added October 21, 2015Reply

    mums is my favorite was also my mom's

    Comment added October 21, 2015Reply

    I love mums!

    Erika Kehlet
    Comment added October 21, 2015Reply

    My favorite perennials are Heliopsis!

    karen mayernick
    Comment added October 21, 2015Reply

    Columbine is my favorite. I love all the different varieties!

    Comment added October 21, 2015Reply

    It's a toss up for me as to which perennial would be my favorite--I love liliums (particularly 'Gold Band' & Star Gazer & Casa Blanca), shasta daisies, and rudbeckias!

    Kate I.
    Comment added October 20, 2015Reply

    Calla lilies are my favorite perennial!

    susan smoaks
    Comment added October 20, 2015Reply

    i really love mums

    Paula Hettman
    Comment added October 20, 2015Reply

    I love irises of all kinds and colors.

    Sandy Zimmer
    Comment added October 20, 2015Reply

    Sedums are my favorite

    Patricia Simpkin
    Comment added October 20, 2015Reply

    I love cone flowers, any color!

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