March: To Do in the Garden

by Gary Crispell, EMGV

March, noun – the third month of the Julian calendar, verb from middle French meaning to trample, (Not in my garden, please.) To move in a direct and purposeful manner (as toward the garden).  Be sure to wear your boots!

By the time y’all read this winter may be gone—or not. We might be able to get into the garden—or not.  It may still be raining three out of every five days whether it needs to—or not. And so goes the Piedmont Carolina winter lament. The magnolia in the front yard never had a chance this year. On a brighter note, it appears that the vast majority of the 350,000 wildflower and pollinator seeds I sowed have germinated. The grand experiment continues. I’ll keep you posted.

The following are the things you should be able to do in March. However, if the current climate pattern continues you may want to consider turning your yard into a large scale rain garden. Hey, they don’t have to be mowed.

Lawn Care
Cool season grasses (Fescue and Kentucky bluegrass) can be fertilized with a non-slow release fertilizer such as 10-10-10. DO NOT fertilize cool season grasses after March 15 and do not use a slow release fertilizer now. Save it for Fall. Fertilizing later than mid-March will increase the likelihood of turf diseases in the heat and humidity of summer.

Apply crabgrass control to all lawns when the forsythia is in bloom and before the dogwoods reach full bloom.

Commence mowing activities when you can do so without losing your mower in the mud. Cool season grasses should be mowed at a height between three and four inches. Warm season grasses are still dormant; Your turn will come later. Mowing frequency should be such that you do not remove more than one-third of the growth.  Leave the clippings on the lawn to help reduce fertilizer needs by up to 25 percent. If circumstances are such that more than one-third has to be cut, collect the clippings and use them as mulch. They DO NOT belong in the landfill.

Feed your shrubbery remembering “moderation in all things.”

Shade trees can be fertilized now, however unless you have poor soil (as indicated by your SOIL TEST) these plants can usually fend for themselves.

Fertilize asparagus beds early in March before the spears emerge.

Emerging flowering bulbs can be fertilized now.

This entire section is based on the rain stopping and the ground not refreezing and actually drying out (whatever that means. I’ve forgotten.)

Trees and shrubs can be transplanted now as well as fruit trees and grapevines up to bud break. Plants planted now will require more diligent water management through the summer than ones planted last Fall.

Perennials can be planted now.

Start annuals and warm season vegetables inside if you haven’t already.  (I know about you first tomato freaks.)

Rose bushes can be planted now.

Cruciferous vegetables (E.g. cabbage, broccoli, cauliflower) can be set out in the garden in the middle of the month.

Root veggies (E.g. potatoes, beets, turnips, carrots) can be planted in March as well as salad greens (E.g. lettuce, spinach, Swiss chard, kohirabi and bok choy) can also be planted in mid-March.

Prune fruit trees.

Dead head spring flowering annuals like pansies (Viola x hybrids) as the blossoms fade to prolong flowering.

Roses can be pruned in the latter half of the month.

Overgrown broadleaf shrubs can still be severely whacked.

Check for the following insect pests:  euonymus scale, juniper-spruce spider mites, hybrid rhododendron borers. Spray as necessary following label directions.

Apply dormant oil to fruit trees to eliminate several insects. This is especially important if you have just pruned the trees.

Spray apple and pear trees in bloom with streptomycin to prevent fire blight.

Stuff to Do to Get Ready for Prime Time:
Check all your gardening equipment to ensure proper working order. You don’t want to spend the first really great gardening day running around looking for parts for your broken garden gizmo.

Think about experimenting with new varieties of annuals, perennials and veggies.  Experimenting is fun and has few lasting side effects.

Photo: Daffodils, credit: A. Laine.

Learn With Us, week of March 1

Raised Bed Gardening CANCELLED
Saturday, March 7 10:00 – 11:00am
For Garden’s Sake
9197 NC-751, Durham, NC 27713

“Raised Beds: If You Build Them the Veggies Will Come” — This class will cover the several advantages of raised bed gardening including recommendations on planning, locating, preparing and constructing the bed. The presenter will also offer helpful tips on season extension, crop rotation, companion planting, improving your soil, using journals to record plant successes (and failures), protection from critters and plant supports. There will also be a discussion of such potential problems and pitfalls as contaminated beds or pest infestations

To register, email or call 919-484-9759

No Leaves, No Problem: All You Need Is A Twig — Tree Identification in Winter

By Wendy Diaz EMGV

If you are hiking in the forest this winter or even ‘intentionally walking your own yard’ (recent post on and want to identify a tree, the best way to identify the species in the wintertime is to use the morphological features of the tree that botanists utilize. To start with, all you need is a twig! 

I recently attended a Tree Identification In Winter Workshop by Matt Jones, Extension Agent, Horticulture at the Chatham County Center in Pittsboro where I was introduced to such precise methods and I practiced identifying twigs using the ‘tools of the trade’1.  To differentiate between character traits of tree species one can use the North Carolina State University (NCSU) Dichotomous Key (Key) developed by Dr. Alexander Krings for our particular geographical region of the Piedmont2. Dichotomous keys start by presenting the user with two sets of plant characteristics in a couplet form, then the user has to select one of the two choices, which more accurately describes the specimen in hand1. The user’s choice leads them to the next couplet and so on until they reach a species name and there are no more choices to make. The Key gives the species name in Latin to avoid confusion from the many common names a tree species can have. An easy way to obtain the common name if you are not familiar with the Latin species name is to use the online NCSU Plant Toolbox3.

The features of the tree which are visible in winter and which are most diagnostic of each species are based on the woody plant morphology which does not include the bark of the tree. Bark can be diagnostic for some trees with very pronounced characteristics like the smooth bark of a beech (Fagus grandiflora) for example but depending on the age of the tree or the position of the bark on the trunk, different bark texture may be observed on the same tree which can lead to confusion and it is not always diagnostic. For the typically difficult genus Quercus or oak, it also helps to look for acorns around the base of the tree as the acorn’s morphological features can differentiate between species.

The main morphological features included in the Key are the following: the arrangement and position of buds, bud scales, arrangement of leaf scars, pith anatomy, number of vascular bundle scars, stipular scars and armament. A hand lens, a set of pruners and a bright area to work in will also help in discerning these relatively small species-specific character traits on the twig. It is essential that the user know the vocabulary4 of the Key, such as but not limited to:

Petiole – The stalk that joins the leaf to the stem.

Alternate – The arrangement is at alternating points from one side of the stem to the other or staggered.

Opposite – The arrangement is on the same spot on stem but on opposite sides of the stem.

Leaf scar – A visible thickened crescent mark on stem where the leaf was attached.

Pith Anatomy: The core of the stem can be homogenous (solid and uniform), diaphragmed (sections), chambered (hollow sections) or excavated (hollowed out).

Diaphragmed: Horizontal breaks in the core of the stem and each section is filled with material.

Bud scale:  A modified leaf that forms a protective covering over the bud.

Valvate bud scale: The scale forms two parts of the coating like a clamshell. 

Bud Scale Scar: The concentric rings formed by bud scales from the previous year’s terminal bud.

Stipular scars: A pair of appendages found on many leaves where the petiole meets the stem, tiny and attached around the stem and can be slit-like or ring-like.

To practice my newly acquired knowledge, I cut a small twig from a tree in my front yard and brought it inside with, to my surprise, a caterpillar.

Twig of tree (3 cm diameter) Photo by Wendy Diaz on January 25, 2020
Caterpillar on tree twig. Photo by Wendy Diaz January 25, 2020

The first step was to determine to which structural group the tree belongs by deciding if the leaf scars were alternate or opposite.  The leaf scars were alternate .

Black arrows–alternate arrangement of leaf scars. Grey arrow-encircling stipular scar.
Photo by Wendy Diaz January 25, 2020

For the second step, the stem had to be sliced longitudally so it’s pith anatomy could be examined. The second couplet asked if the pith was chambered/diaphragmed or homogeneous. The pith of this stem was diaphragmed so the next step using the Key was to proceed to Group 2 where the couplet asked if the stipular scars were encircling the twig or if they were absent.  

Diaphragmed pith anatomy with horizontal breaks in the core of the stem with each section is filled with material. Photo by Wendy Diaz January 25, 2020

The stipular scars were clearly encircling the twig so that lead to the next couplet.

Green arrow – valvate but (two parts). Gray arrow – stipular scar encircling the stem. Photo by Wendy Diaz January 25, 2020

This couplet described the bud as either cap-like and pointed apex or valvate and rounded apex.  These buds were valvate (two parts) with a rounded apex guiding me to the final lead, which is the species name of Liriodendron tulipifera or Tulip Poplar!

Liriodendron tulipifera or Tulip Poplar photo by Wendy Diaz January 31, 2020

The NCSU Dichotomous Key can be a little daunting if you are not a botanist, especially if the tree species you are trying to identify requires multiple couplets and it is at the end of the Key such as Carpinus caroliniana (American Hornbeam). I found clicking on the + symbol next to each couplet, which links to a photo of an example image, is a great visual aid and helped me on whether or not to continue on to the next couplet or backtrack. Practice makes perfect, but if you get frustrated with the Dichotomous Key, you can always wait for spring and the leaves to come out or identify your trees with leaves by attending the companion workshop offered by Matt Jones in September 5.



Online tool: NCSU Botanist’s Little Helper: 2.

Online tool: NCSU Plant Toolbox: 3.



Book References:

Terminology: Plant Identification Terminology An Illustrated Glossary James G. Harris Melinda Woolf Harris second edition

Advanced reference: Woody Plants of the Southeastern United States: A Winter Guide, Ron Lance, University of Georgia Press

Learn With Us, week of February 16

Moss: Primitive and Beautiful – Durham Garden Forum
Tuesday, February 18 7:00 – 8:30pm

Sarah P. Duke Gardens
420 Anderson St, Durham, NC 27708
“Moss: Primitive & Beautiful” with Flora O’Brien, Duke Gardens Volunteer and Extension Master Gardener Volunteer. Moss is a very ancient, primitive plant, and can be enchanting in your garden. It does possess chlorophyll for photosynthesis but does not have flowers or vascular system. Join us to learn more from Flora, the volunteer who cares for the Duke Gardens moss garden.

For any new member joining during the months of February and March 2020, their membership will run through April 30, 2021. Please extend this offer to any of your neighbors, friends, or gardening groups interested in joining the Durham Garden Forum. Our $25.00 membership continues to be an outstanding bargain for the quality of programs/speakers offered. Single program entry fee for non members is $10.00.

Spring Seed Starts
Saturday, February 22 10:00 – 11:00am

Durham Garden Center
4536 Hillsborough Rd, Durham, NC 27705
Description:Starting Seeds for Spring Planting – If you’re hoping to go into the new season with flowers or vegetables or herbs (or all of these), NOW is the time to get both your plan and your supplies together. Topics discussed will include materials needed for successful seed starts; the difference between direct sow and planting indoors; suggestions for proper planting medium; light, water and temperature requirements.

Free/Registration required. Contact:919-384-7526 or