Native vs Non Native gardening

Giant Swallowtail Butterfly on a Zinnia – the flower is definitely not native to Southern Ontario

I recently started following the Royal Horticultural Society on Twitter (@The_RHS); I’m not sure how this feed came to my attention, likely it was Twitter itself, that clever creature, that suggested it.  It was a good suggestion.  Even though it’s a British organization, and the information they share is abut British gardening and British plants and British garden shows, the RHS does, not infrequently, post tidbits that are relevant over here.  Also, their picture are very pretty.

This morning the Society tweeted that the second paper from their Plants for Bugs program has at long last been published.  (The first paper was published in 2015.)

Plants for Bugs is a “a four-year study into wildlife gardening, which was undertaken at RHS Garden Wisley in Surrey…”  as in England, just southwest of London.  The scientists set out to determine what sort of plant typically found in an English garden does best at attracting insects: native or non-native.

Garden commentators in North America have, for many years now, been battling it out (sometimes quite heatedly) over this question.  There are extreme gardeners who ONLY plant natives and those who couldn’t give a whit if a plant is native or not, as long as it looks pretty.  Most commentators fall in the middle – wanting to use natives when possible but not closing the door to aliens (aka non-native plants).

The arguments for using natives run along the lines of they are more drought tolerant (true, but only if it’s a drought tolerant plant to begin with: you wouldn’t stick a native Marsh Marigold – Caltha palustris – in gravelly soil on a south slope); they’re better suited to our climate (until you factor in climate change and how Prince Edward County’s Plant Hardiness Zone has gone from zone 5b to zone 6a in the past 20 years); and they provide better food – nectar, pollen and roughage – than non-natives.

It’s this last assumption that the folks in England wanted to measure.  In 2009, they created 36 planting beds, each nine square metres, and planted some with a mix of plants native only to the UK; other plots had plants that only grow elsewhere in the northern hemisphere while the rest had plants that grow in the southern hemisphere.  Then they waited, and counted the invertebrate life that showed up.

“By the end of December 2013 (four full years of recording) approximately 80,000 invertebrates had been counted and more than 300 species identified.”

The peer reviewed papers that have so far resulted from the study have led the RHS to come up with key messages for the home gardener.  To quote from the RHS site:

From the first paper, that studied pollinating insects:

• The best strategy for gardeners wanting to support pollinating insects in gardens is to plant a mix of flowering plants from different countries and regions.
• Emphasis should be given to plants native to the UK and the northern hemisphere, though exotic plants from the southern hemisphere can be used to extend the season
• Regardless of plant origin (native or non-native), the more flowers a garden can offer throughout the year, the greater the number of bees, hoverflies and other pollinating insects it will attract and support.

From the second paper, that studied insects that chomp on plants, suck the juices from plants or eat other bugs that suck or chew:

• The best strategy for gardeners wanting to support plant-associated invertebrates is to plant a predominance of plants native to the UK.
• Plants native to the Northern hemisphere are likely to support only marginally fewer (less than 10%) invertebrates in some functional groups (including herbivores and some predators) than UK native plant schemes. And exotic plant schemes based on Southern hemisphere plants will still support a good number of invertebrates, albeit around 20% fewer than plants from the UK.
• Regardless of plant origin, the more densely your garden is planted or allowed to grow, the greater the abundance of invertebrates of all kinds (herbivores, predators, detritivores and omnivores) it will support.

 

I’m guessing these messages will appeal to many North American gardeners as well.

For me, the takeaway is to plant densely using a diverse mixture of annuals, perennials, shrubs and bulbs to create as long a flowering season as possible.

Time to revel in Rudbeckia

When I first started gardening (eons ago, it seems) in my tiny Toronto backyard, one of the first flowers I bought was a Black Eyed Susan.  It was lovely – small, hairy leaves with bright orange-yellow flowers in late summer.  I planted it in an area that started out in full sun but gradually, as surrounding trees grew, became shady, which is when I transplanted a chunk of it to the County.  Turns out this was Rudbeckia fulgida var. sullivantii ‘Goldsturm.’  I didn’t know the Latin name then, and didn’t know how many Rudbeckia species were out there and available.

Turns out there are a lot!  At least 25 accepted species with a lot of different common names that can be confusing – one of the reasons I like to use botanical (Latin) names as much as possible.

R. hirta & R. fulgida in same patch

 

In my garden they start blooming in earnest the second week of August and will continue until mid September, longer if dead-headed.  The different species have different ways of spreading — R. hirta and R. fulgida will quickly spread by underground runners as well as self-seeding.

 

 

Rudbeckia laciniata

My favourite tall Rudbeckia (one of my favourite perennials in general) is Rudbeckia laciniata.   I’ve read where it likes moist areas, stream beds and such, but I find that they send their seeds everywhere and will grow everywhere, even in the driest areas of the yard.  They can grow to five or six feet tall but the neat thing is you can, in early summer, clip them back by half or more (as you may do with Asters and Solidago – Goldenrod) so that you keep a clump bushy and shorter.

 

The shorter Rudbeckia‘s do want water — this is after a month with no rain.  The plant came back (you can see new leaves poking through) in the fall but all the flower buds dried to a crisp in the summer.

Orange is the new Black

double orange daylily, possibly Hemerocallis var. kwanso

This lovely double orange daylily is a vigorous grower in moist soil but is easily kept in check in my un-watered garden.  A neighbour gave me a few fans many years ago and now I have several large clumps in the garden.  It blooms later than most every other daylily, helping provide vibrant colour in August before the Asters start to bloom.

 

Lilium lancifolium

Not too sure where I found the Lily but it has been growing in a semi-shaded spot for about 12 years now.  The bulb multiplies underground every year and it also produces small bulbils on the stalk that will ripen over the summer, drop to the ground and help form a small colony.  This Lily is cultivated in parts of Asia as a food source (the bulb).

 

of wasps in gardens…

I’ve noticed that often when someone says the word ‘wasp’ in a conversation or posts the word ‘wasp’ on social media, a general frenzy, almost hysteria, breaks out.  Almost immediately stories will erupt about a friend of a friend or a second cousin or a neighbour being stung by a wasp, or by a whole colony of wasps.  Tragedy is only averted after swift action possibly involving a trip to the hospital.

I get it – wasps are mean looking beasts with big eyes and a venomous stinger that can deliver pain and cause a few days of annoyance.

Some people (I’ve read perhaps 1% -3% of the population) are highly allergic to the proteins that a wasp injects into the skin when it stings.  This could lead to a serious reaction (anaphylactic shock) that requires immediate medical attention.

For me though, fortunately, wasps are merely a nuisance, a flying critter I want to be aware of  because a sting will result in swelling, itchiness, a sore spot for a few days.

A wasp nest can be an indicator of a healthy garden – no out of control pesticide use.  It also means you’ve got an insect ally hard at work controlling the many unwanted insects in your garden.  “Adult wasps typically prey on a wide variety of caterpillars including corn earworms, armyworms, loopers, and hornworms. Adult wasps also utilize beetle larvae and flies as food for their young.”

I’ve found that if I leave a wasp alone it will leave me alone.  They’re attracted to sugary things (which is why they always seem to show up at a picnic involving watermelon or soft drinks) so I watch out near the compost pile after adding melon or peach rinds.  If one starts buzzing around me I’ll slowly move away or gently bat (if that’s not an oxymoron) it aside – I definitely don’t want to agitate it!  There’s all sorts of information out there on how best to move a wasp nest if you absolutely have to (ie if a colony starts to build their own condominium if the beams of your back porch).  I’d suggest though, if possible, to let it be until most die off  in the winter (generally through starvation).

 

 

fun with photoshop…

The Zinnias are HUGE this year!