Aromatherapy Gardener’s Almanac for 2023

By Monika Meulman, CAHP 


Is your green thumb getting itchy like mine? Do you have a hundred seed containers on the kitchen counter vying for your attention? There’s lots to plan. Sort those wonderful ideas into tidy to-do lists so your garden, window sill or front walkways can be full of aromatic plants all through the growing season. Refresh your memory or maybe learn something new from the following gardening guidelines.


Things to Consider and Plan(t) Ahead

  • Check your farmer’s almanac for local frost dates (we’ve added a few sample zones below).
  • Prepare your garden beds, set up an indoor seed starting station or set up vying for your attention outside (see below for tips on warming up soil in the garden).
  • Check the hardiness zone of your favorite new aromatic plants and adjust their growing locations accordingly (see more on plant hardiness below).
  • Choose one or two new plants to try from our recommended best aromatic garden books for 2023.

What are 2023 frost dates?

A frost date is the average date of the last light freeze in spring or the first light freeze in fall. The classification of freeze temperatures is based on their effect on plants:

Light freeze: 29° to 32°F (-1.7° to 0°C)—tender plants are killed

Moderate freeze: 25° to 28°F (-3.9° to -2.2°C)—widely destructive to most vegetation

Severe freeze: 24°F (-4.4°C) and colder—heavy damage to most garden plants


Nearest Climate Station


Last Spring Frost

First Fall Frost

Growing Season Length

Sample Aromatic Locations Of Our Gardens Across The CFA:





Saanichton CDA, BC


Apr 14

Nov 9

208 days

Cupar, SK                                          


Jun 1

Sep 1

91 days

Hamilton Municipal Lab, ON


Apr 20

Oct 27

189 days

Toronto, ON—GTA


May 4

Oct 13

161 days

Toronto Island A, ON (Etobicoke/Mississauga)


Apr 22

Oct 29

189 days

Preston, ON (Waterloo)


May 19

Sep 24

127 days

Ottawa CDA, ON


May 13

Sep 26

135 days

Niagara Falls, ON


May 7

Oct 19

164 days

Windsor A, ON


Apr 28

Oct 18

172 days

Owen Sound Moe, ON


May 14

Oct 9

147 days

Sault Ste Marie Sanderson Fld, MI


May 17

Oct 5

140 days

Coleson Cove, NB                 


Apr 30

Oct 13

165 days


Last and first frost dates are 33% probability calculated using 1981–2010 climate normals from Environment Canada.

NOTE: As our climate keeps changing, these maps will adjust more rapidly. You may also have microzones in your area, due to lake effects, or local depressions in land, where the soil and air stay milder, more days of the year. 


April and May 2023: Prepare your Aromatic Gardens Journey

Warm up soil and keep it warm with these tips:

  • Set up garden plants in a south-facing garden.
  • Plan your garden beds between berms and/or close to walls that absorb spring sun heat.
  • Plant in raised beds and set up covers for beds.
  • Keep black hose outside in sun and use this water to water early spring plants.
  • Set up plastic tunnels for spring plants.
  • Build a mini cold frame with spare parts (like old windows or doors).
  • Put down black plastic and mulch early spring.
  • Put down the black plastic cover on at night, late spring.

Soil and Air Temperature

NOTE: Soil temperatures don’t mirror the air temperature!

There are different processes involved in how heat is moved. For example, 2” below the surface, soil heats up 30% less than the surface maximum temperature, when measured 1 hour after peak air temperature. It’s even cooler deeper down. At 4” below the surface, soil heats up 66% less than the surface maximum temperature, when measured 3 hours after peak air temperature.

NOTE: Soil type affects the heating up of soil.

Soil type for hot and cold:

  • Loam is best: absorbs temperature from the day at medium rate and holds on to temperature well
  • Sandy, fast draining soil changes temperature very quickly and loses heat the end of each day quickly
  • Clay soil holds on to water and rises in temperature very slowly


What is a plant hardiness zone?

(Select your plants for your plant hardiness zone)

Hardiness zone is determined by year-round temperatures, the extreme lowest and highest temperature in a region, and rainfall. Each plant thrives in a variety of regions and a range of hardiness zones.  Most plants will grow just about anywhere but will NOT survive the winter. When plants grow in a harsh environment, they show stress with stunted growth, lacking flowers or not producing seeds. When a plant survives the winter climate in your region, it is considered a perennial. If it does not survive your winter climate (or even extreme heat summer climate) it is considered an annual in your area.

Some plants also have a natural annual cycle where they grow from seed, flower, release seed and then die off. They are considered true annuals.

You can alter your local hardiness zone by creating garden bed covers; wrapping your rose bushes, shrubs and evergreens in burlap; or planting sensitive plants in pots (in the garden grounds) that you remove and place in a cool room indoors over the winter months.

Check your zone here:


Aromatic Plant Lovers Wanted

Plan out your planting guide now. Follow these growing guidelines to get started.

Spring Aromatic Planning—Herbals & Flowers

Plant common name

Latin name

Hardiness zone



Salvia rosmarinus


New plants: start/grow indoors until all risk of frost has passed

Can grow from cuttings anytime

Prune back in August/September to reduce size in garden and protect it

Garden Sage


Did you know:

There are over 900 species of Salvia?

Salvia officinalis



Perennial in zones 5–8


Annual in zones 9–10

Blooms in summer, plant from seed on date of last spring frost

Start seeds indoors 6-8 weeks before last frost date


Sage does NOT tolerate humidity and does well in temperate climates


Prune back in early spring before growth begins

Spanish Sage

Salvia lavandulifolia


Highly aromatic, very purple flowers like lavender

Start from seed indoors: March/April, outdoors: May/June

Did you know that S. lavandulifoliacan improve word recall?

White Sage

Indigenous to North America (Southwest)

Did you know that Salvia melifera (black sage) is also indigenous, but much smaller.

Salvia apiana


Takes up to 3 years to mature

Small growing habit, grows 2–3’ tall

Transplant it indoors for the winter months

It’s common for the seeds to have only a 20–30% germination rate.

Peppermint, Spearmint, Apple Mint, Chocolate Mint, Water Mint, Egyptian Mint

Mentha genus


Depending on variety



Summer Aromatic Planning - Herbals & Flowers


Plant common name

Latin name

Hardiness zone



Rosa damascena


Cut back cultivated varieties as needed

Prune back damaged plants in the fall, otherwise no pruning needed for wild plants


Rosa centifolia


Harvest rose petals for rose water summer to early fall

Harvest rosehips after first frost


Origanum majorana


Grows well in hot gardens

Plant annually in colder climates

Lavender, most varieties

Lavandula genus


Lavandula angustifolia is best planted from starter plants after soil is warm. It thrives above 15 C°

Many varieties grow well from cutting soft wood and using rooting powder.

Prune about ⅓ of top of plant but don’t cut old wood; only cut back fresh, new growth


Ocimum basilicum


Basil loves the sun but in hot climates, zones 9-10, keep your basil shaded mid-afternoon

To promote maximum aromatic basil leaf growth: pinch off flowers and grow in soil not too rich in fertilizer

Use mild compost tea every 2 weeks to fertilize

For strongest aroma, pick leaves in the morning

Tulsi/Holy Basil

Ocimum sanctum


Start seeds indoors (it grows naturally in India and prefers warm weather)

Move outdoors into garden or containers after May 24 weekend

Only grows to about 1’




Fall Aromatic Planning  – Herbals & Flowers


Plant Common Name

Latin Name

Hardiness zone


Eternal Fragrance Daphne

Daphne transatlantica


Plant in spring or fall

Grows 2–3’ tall and wide

Propagate by cuttings

Grows well in light shade

Aromatic notes of sweet-n-spicy, fruity, fresh


NOTE: toxic to pets and humans

Fragrant Angel Coneflower


Did you know this cultivar averaged the most pollinator visits, including most butterflies, of any coneflower in an Echinacea Trial, at Mt. Cuba Center in 2018/2019

Echinacea purpurea


Native to North America, this is a hybrid species, highly fragrant

Aromatic notes of vanilla and baby powder

You can propagate these beauties by division in spring or fall and root cuttings in the fall or early winter

Freely self-seeds

Flowering Tobacco Plant


Originated in Argentina

Did you know that flowering tobacco plants are verpertines?

(flowerheads remain closed during the day and open as night falls)

Nicotiana sylvestris


Large! Specimen; grows 6–8’ tall

Aromatic notes of jasmine


Bonus evening garden delight: the flowers open in the evening



Happy aromatic planning and planting!


Your garden steward, aromatically yours,

Monika Meulman



Herbicide effects of essential oils Published online by Cambridge University Press:  20 January 2017


Top 5 (NEW) Books on Aromatic Plants & Growing your Green Thumb


The Seasonal Gardener: Creative Planting Combinations

    Hardcover, April 20, 2022, by Anna Pavord

    Gardening For Everyone: Growing Vegetables, Herbs, and More at Home

      Hardcover,\ March 8, 2022, by Julia Watkins


      A Greener Life: Discover the joy of mindful and sustainable gardening

        May 4, 2023, by Jack Wallington


        New Naturalism: Designing and Planting a Resilient, Ecologically Vibrant Home Garden

          Hardcover, Feb. 16, 2021, by Kelly D. Norris


          The Ultimate Flower Gardener’s Guide: How to Combine Shape, Color, and Texture to Create the Garden of Your Dreams

            By Jenny Rose Carey

            Bonus Book!


            We Are the Ark: Returning our gardens to their true nature with acts of restorative kindness

            Reynolds, Mary


             Check out these resources for more aromatic plant know-how:

            15+ Aromatherapy Books for Free!



            Six research articles/reviews on essential oils for furthering your studies:

            Essential oil therapy in rheumatic diseases: A systematic review. Viviane Lucia Barão Paixão 1, Jozélio Freire de Carvalho 2
            PMID: 33865080 DOI: 10.1016/j.ctcp.2021.101391

            Peppermint essential oil: its phytochemistry, biological activity, pharmacological effect and application
            Hui Zhao 1, Shan Ren 2, Han Yang 2, Shun Tang 2, Chenyang Guo 3, Maolun Liu 2, Qiu Tao 2, Tianqi Ming 2, Haibo Xu 4
            PMID: 35994817 DOI: 10.1016/j.biopha.2022.113559

            Essential Oils – An Overview. Elisabeth Anderson; Jinpeng Li - August 17, 2020. 

            Essential Oil of the Plants Growing in the Brazilian Amazon: Chemical Composition, Antioxidants, and Biological Applications. Oberdan Oliveira Ferreira 1 2, Jorddy Neves Cruz 3, Ângelo Antônio Barbosa de Moraes 2, Celeste de Jesus Pereira Franco 2, Rafael Rodrigues Lima 3, Taina Oliveira Dos Anjos 4, Giovanna Moraes Siqueira 2, Lidiane Diniz do Nascimento 2, Márcia Moraes Cascaes 5, Mozaniel Santana de Oliveira 2 3, Eloisa Helena de Aguiar Andrade 1 2 4 5
            PMID: 35889245 PMCID: PMC9318482 DOI: 10.3390/molecules27144373



            Prepubertal gynecomastia linked to lavender and tea tree oils

            Derek V Henley 1, Natasha Lipson, Kenneth S Korach, Clifford A Bloch

            Affiliations expand

            PMID: 17267908 DOI: 10.1056/NEJMoa064725

            Published for:

            National Institute of Environmental Health Sciences.  As a publicly-funded institute, NIEHS is committed to conducting the most rigorous research in environmental health sciences, and to communicating the results of this research to the public.

            Medicinal and Aromatic Plants, Sample Chapters. Akos Mathe, Faculty of Agriculture and Food Science, University of West Hungary, Mosonmagyaróvár, Hungary.



            About the author: Monika Meulman has been a practising aromatherapist for more than 20 years. She embraces a combination of Eastern and Western approaches to holistic healing and offers custom blending for her clients. She is the owner of The Healing Muse Apothecary and has been working with plants, oils and gardens for more than 25 years. She teaches wellness, community and workshops in the GTA and online. Most recently, she has been studying animal spirit medicine and working with energy medicine such as reiki and body readings. You can learn more about Monika at

            Photo credit: Monika Meulman