Native vs Non Native gardening

Butterfly & Zinnia cm

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.

Sunflower August 2017

Time to revel in Rudbeckia

Rudbeckia Laciniata, August 19, 2011

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.

Rudbeckia

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 Aug 6 2017 a

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.

 

deadish Rudbeckia July 29, 2012

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.

mid summer report – happy happy joy joy

Nothing has died.

That kind of says it all.  This time last year the fields were brown, the Larix were dead, the Rudbeckia was just not flowering.

Copious amounts of rain this spring and an average amount so far this summer has brought in the garden great joy to all things growing and, I suspect, all things crawling and slithering and hopping (hello newly arrived rabbit family!) as well.

Here are a few updates from previous posts.

The Canadian Burnet (Sanguisorba canadensis) purchased and planted on July 1 is now blooming: Sanguisorba canadensis July 29 2017

The Cup Plant (Silphium perfoliatum) started from seed and planted out last year is now eight feet high and blooming:Silphium perfoliatum July 29 2017

Garlic planted last fall has been harvested, and my experiment to see if cutting off the scapes does increase bulb size shows me yes, it does:

Garlic - with and without scape removed...

left – scape cut off; right – scape not cut off

Veggies are all doing well with no or minimal watering – have harvested beans, chard, zucchini, green onions; the spaghetti squash and tomatoes are getting plump:

This Phlox, given by friends, almost didn’t make it last year.  So glad it hung in to produce this glorious display now:Phlox July 30 2017

Directions from Nature

When early pioneers were rolling their way across the tall grass prairies of North America, sometimes, in mid summer, they would come across a towering plant with huge basal leaves that often were oriented on a north-south axis.  They called it a Compass Plant.  In later years scientists speculated the leaves point that way to protect themselves from the burning sun.  The plant would be labelled Silphium laciniatum – the same genus as the Cup Plant (Silphium perfoliatum) that I wrote about earlier.

It’s easy to see why – they’re both really tall (the Compass Plant can grow to 12 feet high) and both has relatively small (2″ – 4″) sunflower-like flowers.  Carious types of bees love to feed in the flowers and their stalks, if left up all winter, can provide over-wintering refuge for beneficial insects as well.  They differ in that the Cup Plant likes moist meadows and tolerate flooding in spring while the Compass Plant, being native to the prairie, likes it dry and can tolerate drought.  (After next to no rain during last year’s spring and summer drought, they’ve back in my dry back field more vigorous than ever.)

This is likely because Compass Plants have a really long taproot (up to 16′ deep in the prairies!)  that seeks out moisture, even in the rocky, decidedly non-prairie like soil of the County.  This root can, unfortunately, make it really challenging to transplant – best to start seeds and plant them where they can stay for many years.  They can self-seed but it’s not a fast process – my 15 year old patch has produced only three offspring that I know of, two in the gravelly rocky area where the ‘parents’ live and one in a meadow, about 30 feet away.  One plant with a single flowering stalk can, however, become one plant with multiple flowering stalks.

If you can find Compass Plant for sale (perhaps at a local native plant nursery)  and you have room, buy it; or, if you find seeds somewhere (Seedy Saturdays in Picton or Trenton possibly) , try starting them yourself.  (Read up on how to prepare them for sowing first.)

Tale of Two Echinaceas

I have to confess I don’t have just one favourite plant – I have dozens.  And the list changes every year depending on things as mundane as the weather (too dry to produce many flowers, or, so dry the whole plant just dies) or as esoteric as did I grow it from seed (or it was given by a friend or relative).

Bug on purple echinacea (2)

Echinacea purpurea

In mid July there are quite a few favourites – one of them is Echinacea purpurea – Purple Coneflower. It has lively purple or white (the alba variety) large daisy-like flowers, self seeds readily and transplants easily.  Best of all, bees and other bugs love its pollen and nectar.  If it’s happy in its location it can get quite tall so needs to be either near the back of a border or in the midst of other tallish things.

bugs on white echinacea
Echinacea purpurea alba

 

 

 

 

 

My newest heartthrob though is Echinacea pallida – Pale Purple Coneflower.    I started these indoors from seed two winters ago; last year I planted them out – kinda spindly looking things with short narrow leaves.

IMG_2433_edited-1

Echinacea pallida the first yeat – longish narrow leaves very different from E. purpurea

No sign of a flower at all.  They survived the drought though, with minimal watering, so that made me happy.

Echinacea pallida July 2 2017

Echinacea pallida July 2 2017

This year they exploded – almost literally – sending up first much larger leaves and then enormous stalks topped with a beautiful and delicate flower.  Much like the Purple Coneflower, except it differs by having narrower petals that droop down instead of pointing out like a daisy.

 

Also, the flower stalk itself is many inches long, making it perfect for cutting.

Ti top it off, as the Missouri Botanical Garden plant page says, this native plant can: “tolerate Deer, Drought, Clay Soil, Dry Soil, Shallow-Rocky Soil.”

In other words, this perennial is perfect for my garden and also for many other gardens in the County!

Let me know if you’re interested in growing these yourself – I’ll try to harvest and save you some seeds.

Echinacea pallida July 8 2017

Echinacea pallida July 8, 2017

New Additions

I really enjoy visiting nurseries – especially the small owner-operated ones that specialize in specific types of plants.  You can often find things that don’t make it to the larger nurseries, let alone the supermarket parking lots.  The people working there (ie those owner-operator types!) are a wealth of knowledge about what grows well in a local area, what survived last year’s drought and how tall something might really get!

On  Saturday, to celebrate Canada’s 150th birthday, I went with some friends to Fuller Native & Rare Plant Nursery in Belleville, Ontario.  I’ve never been before but found out about them at the Picton Seedy Saturday earlier this year.  What a jewel!  This tiny nursery has four small structures jammed with trees, shrubs and perennials in pots 4″ to five gallon – including many in an ‘end of season’ sale – five 10 cm ‘plugs’ for $10.   (They call them plugs, to me they’re tall 10 cm pots.)

Anyway – love this place, their display beds are outstanding – all full of colour and ideas.  I walked out with some 10 cm plugs of Empatorium purpureum (Joe Pye Weed) and Helenium autumnale (Sneezeweed) plus two plants that are new to me:  Sanguisorba canadensis (Canadian Burnet):

Sanguisorba canadensis[Canada Burnet]

The Canada Burnet really does like moist, even marshy areas….gets about a meter high and will have load of interesting white spikey flowers in summer/fall

and Thermopsos Villosa (Carolina Lupin):

Thermopsis villosa [Carolina Lupin]

The Carolina Lupin has bright yellow flowers in the summer; should mature to about one meter high and wide.

Didn’t know anything about their habit or needs but they looked great planted out at the nursery.  A quick internet search indicates the Thermopsis should do well – it can take dry, clay soil, while the Sanguisorba might find it more challenging as it likes moist areas.

But hey, it survived through last year’s drought at the nursery with no hand watering – and we’ve just come through the wettest spring in a century, so here’s hoping!