Q: I like using varied scents in my plantings, to enhance the garden experience and add delightful little surprises. I already grow a number of the more commonplace native and nonnative plants, many of which are sweetly perfumed, but do you have a few ideas for something different and unexpected?
A: Small yellow daisies don’t tend to have notable scents, so I love the delicious surprise that Berlandiera lyrata offers. Its common name is the spoiler — chocolate daisy — and I can vouch for the fact that it truly smells like chocolate. It’s native to the southern U.S. and Mexico, but can be somewhat hard to source. A perennial that is hardy here on paper, it might not actually return every year if soil drainage is poorer than your average dry-climate grassland to which it is adapted. Still…chocolate! Worth having to replant, if you ask me.
A subshrub grown as an annual (due to its being not-quite winter hardy here) with fine downy, silvery leaves brings an aroma of curry when rubbed. Appropriately called curry plant (Helichrysum italicum), it’s sometimes sold among other culinary and aromatic herbs at area nurseries. This is not one of the plant species used in making curries, though, which look and grow differently. This Mediterranean native would make a good companion with the above or with other herbs in a sunny spot that never stays soggy.
Tree foliage is an element of the garden we don’t expect to smell, other than the general, earthy tones of mid-autumn. If you have the space, my favorite exception is the scent offered by falling leaves on katsura (Cercidiphyllum japonicum). With leaves shaped like redbud (only tinier) and the mature stature of a shade tree, it always takes me a minute each fall when I encounter one to realize I’m not smelling a nearby bakery. Mildly sweet, slightly-spiced scents waft around as the leaves drop for the season. Never fails to make me want a pastry. There are a handful of katsura cultivars that provide either great spring foliage color or a weeping habit to rival the most graceful weeping willow.
Q: I was a bit surprised by the amount of pests and diseases that my native plant garden accumulated this year. Was it just a fluke year for problems, or is this climate change at work? Is it just because my garden itself is fairly new?
A: Each year’s weather patterns can have different impacts on the severity of a pest or disease outbreak, since both insects and pathogens rely on environmental conditions like temperature and moisture levels to grow and proliferate. Climate change is altering weather patterns as well as the distributions and survival ability of organisms, so we can’t completely separate these impacts.
New gardens can take time to be “broken-in,” so to speak, where the soil disturbance from planting gradually resolves itself and the plants settle in to their new community of soil microbes, interactions develop between plants as they mature, and the local wildlife — beneficial and otherwise — discovers this new resource. It’s not unreasonable to expect a younger planting to face more challenges than a more established one, though sometimes the opposite can be true because pests may not stumble upon their host plants right away if they’re not in the immediate area already.
I often hear about gardeners’ expectations or assumptions that native plants are less prone to problems by virtue of the fact that they are native. This generalization, while well-intentioned, is not true as a blanket statement. Plenty of native plants can contract cosmetic or even debilitating diseases, and most have their share of pests as well. (Keep in mind that many of those pathogens or pests are native organisms also.) One of the reasons invasive species are so successful, and part of the reason non-natives became so mainstream, is because they have relatively few vulnerabilities to the local pests and diseases.
This is not to imply that native plants are problem-prone, as that would be a generalization going too far in the other direction. Instead, we need to remind ourselves that plants are going to be more prone to any problem when they’re stressed, and plants well-matched to their site conditions are less likely to experience stress overall.
Good plant species diversity is key to helping us avoid the issue of plant problems in the garden. Not only will diversity boost the resiliency of the planting as a whole (because even generalist pests and pathogens often don’t impact all garden plants equally, native or otherwise), it will also temper our perception of garden eyesores that need addressing. When a mildew-laden beebalm or rust-marred ironweed is not the only point of interest, its issues more readily fade into the background. While the impact of such issues on the individual plants remains the same, their impacts on us in turn are diminished, which in many ways is all that matters.