By Dean Nernberg
While homeowners across Canada can reap great benefits and enjoyment from using native plants in their gardens, there are some considerations to keep in mind when selecting specific species.
One of the major factors limiting the use of native plant species is the lack of availability. It may be difficult to find suppliers that sell native species. Check with garden centres or small nurseries in your region to see if they either grow native plants or distribute them from other growers.
Genetically pure versus horticultural
Another factor to consider is whether you want ‘genetically pure’ native plants; that is, plants that occur naturally without any scientific interference. Thanks to selective breeding, many horticultural varieties of native plants have been developed. These varieties may have longer flowering periods, distinct flower colours and/or different growth habits compared to their genetically pure counterparts. In addition, they will likely be more readily available at commercial nurseries and greenhouses.
The variety you choose will depend greatly on your own personal gardening objectives. If conserving local genotypes is important to you, you might want to cultivate pure native strains of plant species found in your region. However, if the overall appearance of your garden is more important, you might opt for horticultural varieties that exhibit certain characteristics and benefits.
When using native plants, many gardeners do not pay much attention to the plant’s natural reproductive capabilities; in other words, its ability to propagate and produce new plants by seed or by spreading rhizomes (underground stems) or stolons (runners).
Many horticultural plants are sterile and do not spread; however, native plants usually have the ability to reproduce. This isn’t necessarily a bad thing, but it does mean you may end up with many more plants than you bargained for a few years down the road. For most species, this would not be a concern, but for some it may mean annual maintenance, to remove little seedlings or control the spreading nature of some plants.
If phrases such as ‘spreads naturally’ or ‘naturalizing’ are used on the tag or information label of a plant, ask more questions to determine whether it will be suitable for your landscape design plans.
A number of species-specific factors can influence your chances of success, beyond just whether these plants are native to your region. If you want your garden to look spectacular, you must give your plants all the resources they require to perform well and select species that are naturally suited to the conditions of your garden. The main factors you want to address are:
- Soil type: Is your soil heavy clay, loam or sand? Is it well drained or low-lying and periodically flooded?
- Aspect or exposure: Is your garden south-facing, hot and dry, or north-facing, cool and moist?
- Moisture availability: Is the soil wet or moist all the time or well drained and dry? Are you prepared to augment natural precipitation with manual watering or irrigation?
- Drought tolerance: What are the moisture requirements of the plants you want to use? Do they need consistent moisture or can they withstand periods of drought?
- Light requirements: How much sunlight does your garden receive each day—full sun (at least four to six hours), partial sun (two to four hours) or shady (filtered light with little direct sunlight)? Does the amount of daily sunlight differ from one part of the garden to the next?
This is 2 of 5 in A Guide to Gardening with Native Plants