Pagoda dogwood branch with leaves, Cornus alternifolia.

Ontario Native Plant Growing Guide for June

June is one of the most delightful months in the garden. Summer is finally here in all her glory as everything becomes green and lush. While there is still lots of work to do, this is the time to slow down and enjoy all that nature has to offer. In this Ontario Native Plant Growing Guide for June post we will talk about planting seedlings, mulching beds and some of the superstar plants for June.

Planting Seedlings

June is an excellent time to plant seedlings in your garden. The weather in Ontario is usually still mild with some rain. In July the weather will be too hot and dry for your seedlings, so make sure to get them planted now.

Water your plants well for the first few weeks. Once they have established their root system they shouldn’t need any additional water. Since we had consistent rainfall last summer I gave my seedlings an initial watering and never watered them again.

Spotted Joe-Pye Weed (Eutrochium maculatum)

Mulching

It is very important that your soil is always covered with some sort of organic layer. In healthy natural ecosystems you rarely see bare soil. If you do, it might be a sand dune in a beach ecosystem or a desert.

After planting and watering well, I spread a layer of mulch, making sure the leaves of my plant are above the mulch and exposed to the sun. I use anything I have on hand to cover the soil. Grass clippings, wood chips, sawdust, leaf mulch. They all work well. Mulch keeps the soil cool, prevents water loss from evaporation, prevents weeds from germinating and keeps soil organisms happy.

Common Boneset (Eupatorium perfoliatum) with a layer of leaf mulch

June Superstars

Flowering in June

Blue Flag Iris (Iris versicolor) is a stunning plant for a moist location with full sun. It blooms for almost the entire month of June, and would look fantastic mixed in with other moist soil species that will bloom later in the season such as Joe-Pye Weed (Eutrochium maculatum), Common Boneset (Eupatorium perfoliatum), Flat-topped White Aster (Doellingeria umbellata) or Purple-stemmed Aster (Symphyotrichum puniceum).

Red Columbine (Aquilegia canadensis) is a versatile plant, it will grow in both sun and shade, with medium moisture levels. It is short lived, but self sows freely.

Common Yarrow (Achillea millefolium) is a drought-tolerant plant that enjoys tough growing conditions. Our plants are growing in sandy, nutrient-poor soil in full sun, and they love it. If you have a difficult area of the garden where nothing grows, Common Yarrow might be a good choice. It can be aggressive and spreads by rhizomes. Plant it in a container if you would like to keep it from taking over. This plant will bloom for most of the summer and is a pollinator favourite.

Other Plants for Garden Interest in June

Red Elderberry (Sambucus racemosa) is one of our two native Elderberries (the other is Common Elderberry, Sambucus canadensis). Not all of my superstar species are flowering in June; Red Elderberry flowers in May, and then produces brilliant red berries in June. The berries won’t last long, birds will quickly devour them.

Sedges are secret superstars. In the garden they provide a lush green backdrop for some of the showier wildflowers. Ontario has almost 250 different sedge species, which means there is a sedge that will grow in almost every light and soil combination. Fox sedge (Carex vulpinoidea) grows in moist soil in sun to part shade (pair it with Blue Flag Iris!). Drooping Woodland Sedge (Carex arctata) grows well in dry shade, often a difficult area to find suitable species.

Ferns are another secret garden superstar. They can be quite large, such as the familiar Ostrich fern (Matteuccia struthiopteris) or Royal fern (Osmunda regalis), or small and delicate, such as the Oak fern (Gymnocarpium dryopteris) pictured above. We will have a variety of fern plants for sale this year, you can purchase them when we are at farmers markets or by local pick up in Uxbridge, Ontario.

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