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  • Upcoming events in Middle Tennessee

     

    Save the Date: Perennial Plant Society’s 30th Plant Sale is April 4, 2020, 9 a.m. – 1 p.m. at the new Expo 3 Building at The Fairgrounds Nashville. Here’s where you can find the newest varieties of perennials, shrubs, vines and annuals from local growers, along with long-time, never-fail favorites, ready for spring planting. Learn more at the PPS website.

     

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Mulching trees; and a stack of new books

QUESTION: How should mulch be put around trees — piled high or spread even with the ground and good edging to keep water within?

Unfortunately, this is not the best way to mulch trees.

There are many good reasons to use mulch around trees in a landscape. It keeps the soil warmer in winter and cooler in summer; it helps the soil retain moisture; it helps control weeds, and improves soil fertility by adding organic matter. It keeps mowers and string trimmers at a safe distance from the tree trunk, plus, it looks nice.

There are a few “rules” for proper mulching, but none of them include piling mulch up high around the trunks of trees. In fact, it’s a bad idea. Here’s why:

Plants need oxygen in the soil, and mulch that is too thick – more than 4 inches – restricts the soil oxygen exchange, according to the UT Extension’s publication on mulching trees and shrubs. Roots will grow up to find more oxygen, instead of down and outward through the soil. Too much mulch also causes too much moisture in the root zone, making roots susceptible to rot, insects and diseases. Cracking in the bark creates an entry point for insects and fungal growth, and invites rodents to chew the bark and damage the trunk or even girdle the tree – destroying the bark all the way around, which is a quick cause of a tree’s demise.

Unfortunately, this so-called “volcano” mulching, with the mulch placed in a cone around and next to the trunk, is a common practice. Here’s the proper way to place mulch, according to UT Extension (and other good sources):

Apply mulch in a ring no more than 2 to 4 inches deep, at least 4 to 6 feet in diameter around the base of the tree. Place it so that it tapers out to the ground level at the edge of the ring. Do not pile the mulch around the trunk; pull it several inches away so that the base of the trunk is exposed and air moves freely.

Spring reading

There are several new gardening books out this spring. Here’s a roundup:

* I’m slowly making my way through Women and Their Gardens: A History from the Elizabethan Era to Today, by Catherine Horwood (published by Ball Publishing, an imprint of Chicago Review Press). Focusing on the fact of history that women have often been excluded from the serious study of plants, Horwood brings these women into their rightful place in the horticultural spotlight. At more than 400 pages, there is much to be discovered about these pioneering women. I have just learned, for instance, that in 1897, Beatrix Potter was snubbed in her attempt to present research on spore germination of a rare form of fungi. She went back to private research and to her other specialty, detailed watercolor illustrations. A hundred years later, the artist famous for her beautiful childrens’ book illustrations was honored by the Linnean Society with a distinguished lecture entitled “Beatrix Potter as Mycologist.” So there.

* You may remember Graham Kerr as a cookbook author, TV personality and chef who called himself The Galloping Gourmet. His new book is Growing At the Speed of Life: A Year in the Life of My First Kitchen Garden (published by Perigee Trade Paperbacks). He acknowledges from the first page – from the cover, really – “As the Galloping Gourmet, I cooked just about everything that grows – but I’d never grown a thing I’d cooked.” He set out to change that, and the book outlines much of what he learned in that year, and what he expects to learn about growing food in the years ahead. It’s a charmingly personal account, and with a shout-out to “First Lady Michelle Obama putting spade to turf on the White House lawn.” His focus is on the basics, the favorite vegetables and most-used herbs, and with recipes, of course.

* Local gardener and garden blogger Barbara Wise, author of Container Gardening For All Seasons (published by Cool Springs Press) makes assembling gorgeous containers easy by providing, cookbook-style, “recipes” and shopping lists and assembly instructions for about 100 container combinations. (My thanks to Barbara, because I heard about the book just as I was compiling information on container planting for the “Grow a Green Thumb” class I’m leading right now for Lipscomb University’s Lifelong Learning series. What a great resource!)

* For the more ambitious gardeners who include fruit-growing in their garden and landscape plans, there is Grow Fruit Naturally: A Hands-On Guide to Luscious, Homegrown Fruit, by Lee Reich. In my semi-sunny garden, strawberries (apparently, to feed the rabbits) and blueberries (for the birds) are about as far as I’m willing to venture into fruit-growing territory, but if you’re serious about getting fruit from tree to table, this book is for you. It helps you plan, choose and maintain plants in the garden or in containers, and learn ways to control (or avoid) common pests and diseases without toxic sprays. I did just buy a ‘Meyer’ lemon shrub to add to our container collection of things that need to be pampered, so maybe this will help us keep it alive. The eye-candy photos make leafing through the book a pleasant distraction. It’s published by Taunton Press.

* Speaking of nice photos, Rodale Books has published The Photographic Garden: Mastering the Art of Digital Garden Photography, by Matthew Benson, a professional photographer and contributing editor to Organic Gardening magazine. Since part of the joy of gardening is taking pictures of what you grow and sharing them with other gardeners, it would be lovely to know how to do it beautifully. Read the book before the next time you take your camera out, and maybe your garden photos will jump to the next level right away.

* Finally, in the stack of new books: Vegetable Gardening the Colonial Williamsburg Way: 18th Century Methods for Today’s Organic Gardeners by Wesley Green (also published by Rodale). Do you grow salsify? Have you ever heard of skirret? These may not be at the top of everyone’s list of favorite vegetables, but in the 18th Century they were likely growing alongside the onions, garlic, melons, chives, sweet potatoes, beets, parsley and many other things that are familiar in our gardens, and they grow now at Colonial Williamsburg, one of the nation’s best historical preservation sites. The focus in this book is the traditional cultivation methods that are still good for today’s organic gardens. Green, the author, founded the Colonial Garden and Plant Nursery in the Historic Area of Colonial Williamsburg and he and another gardener, Don McKelvey, study and interpret 18th-Century plants, tools and techniques. This book is the beautiful record of that impressive work.

 

Iris time in Tennessee

QUESTION: When is the right time to divide irises?

Bearded irises can be divided after they finish blooming.

Bearded irises, the large, showy flowers that have fuzzy patches on the outer petals, are putting on a pretty nice show across the region right now, and they’ll continue to bloom for several weeks.

After they have finished blooming, the rhizomes can be thinned out and divided if needed. But if you don’t get to it right away, you can wait until later. Irises are resilient and can survive being moved as long as they are re-planted properly.

Garden expert Judy Lowe recommends this method in her book, Month by Month Gardening in Tennessee & Kentucky:

Cut the leaves into a 6-inch high fan shape, then lift the clump with a spading fork and gently wash the dirt from the tubers. Cut off any soft, mushy or damaged parts, then cut the rhizome into smaller pieces, each with an eye or bud, using a sharp knife.

Lowe recommends dipping each rhizome into a fungicide solution to reduce the chance of fungal problems; one part liquid bleach to nine parts water is one suggestion to use.

Replant the rhizome sections close to the soil surface and water them well. Rhizomes of bearded irises should be planted so that their tops are visible above the soil. Iris beds should not be mulched.

In general, you may need to think iris beds every three to five years.

News & Events

Nashville garden specialist Barbara Wise has a passion for pots – that is, planting and growing container gardens. She now has a new book out: Container Gardening For All Seasons.

“I wrote it for new gardeners and for those who like simple (easy) steps to follow that will help them succeed as gardeners,” she says.

The book features 101 container “recipes” that any novice gardener can follow – she tells what plants to buy, what size container to use, how to place the plants, and substitutions to consider if you can’t find (or don’t like) the suggested “ingredients.” But it’s also nice for experienced gardeners who are looking for new ideas. It’s published by Cool Springs Press; retails for $19.99 and you can order it through Parnassus Books and Amazon.