Native vs Non-Native-Which is Better for Pollinators?

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Tithonia, Mexican Sunflower, native to Mexico and Central America, is one of the top insect drawing plants in my garden

Native Vs Non-Native

Native or non-native in the garden: Which is better? Simple- everyone knows the answer to that question…Natives of course! As gardeners, we have been bombarded with information about the value to wildlife of native plants and the more natives the better. But the definition of natives has always been fuzzy to me. Are natives plants that originated within our region, state, or North America? Or things that predate Europeans settling North America? Or does it mean plants indigenous to a particular habitat or ecosystem? And how about cultivars of native plants-like different varieties of Anise Hyssop which is a North American native? There are no easy answers to these questions.

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‘Pink Panther’ Anise Hyssop is a bee magnet
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Liatris is a great native wildflower that I grow for bee value

I have always been skeptical about the native plant zeal and ready to challenge it after my observations of over 50 years of gardening experience. My blog post on the benefits of planting Butterfly Bushes stirred up some controversy. I acknowledge that Butterfly Bush provides only nectar and not foliage value to caterpillars as a host plant. But I still urge people to plant Butterfly Bush because deer won’t touch it and the butterflies flock to it and I enjoy the plant for its beauty and ease of growth. There aren’t many flowering shrubs that deer leave alone which makes it valuable as a landscape plant.

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Pipevine Swallowtail on Butterfly Bush flower

I always deferred to the experts about native plants because anecdotal evidence is not the same as peer reviewed scientific articles.  So, I had no numbers to back up my belief gained from experience. Planting a diverse assortment of flowers- be it perennials, vines, annuals, trees, or shrubs or native and non-native to provide a healthy and beautiful habitat was always what I have practiced. My decisions on what to plant was determined by whether the plant was appropriate for the location and environment, not fussy, and that it wasn’t invasive.  Invasive means that a plant is spreading prolifically and undesirable or harmful to the habitat.

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A roadside field of invasive Purple Loosestrife,, Lythrum salicaria, originally from Europe
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Invasive Japanese Beetles feeding on Lythrum

Plants For Bugs Article

My longtime observations of planting a diverse selection of plants, both native and non-native, was recently backed up by an article, “Plants For Bugs: all in the mix” by Helen Bostock, who is a RHS Senior Horticultural advisor, from across the pond. Bostock says the average UK garden contains around 70 percent non-native and 30 percent native plants. I couldn’t find the U.S average, but I think it is probably very close to that same percentage. Bostock concludes that native use is on the rise, especially with the ‘back to the wild’ environmental movement, and ongoing education of home consumers of landscapes. I see it happening in my own practice of landscape designer with more and more requests for butterfly/wildlife friendly landscapes and less requests for manicured formal gardens. Gardens are still very unlike natural habitats but have a much greater diversity of plant species than their surroundings which have been degraded with development encroachment.

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Zinnias are not native to my area but pollinators love them

Bostock’s research concludes after studies spanning four years that a mix of plants from around the world may be the most effective way to sustain pollinators. This was no surprise to me. The native bandwagon has acquired mystical connotations in the past 10 years and claims that natives use less water, are disease free, and low maintenance have been made over and over.

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I am slowly removing turf and planting meadows with native plants on my property

But what role do garden plants (both native and non-native) play in supporting wildlife?  Views differ on whether planting native plants only is necessary for the most wildlife friendly garden. This was the question posed by the Wildlife Gardening Forum in the UK and they set up a field experiment designed to test whether the geographical origin of a plant affects the numbers and diversity of insects and other wildlife.

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Pollinating fly on mint flower

Conclusions

This is what the RHS study has concluded:

• Research reveals a mixture of native and non-native ornamental plants may provide the best resources for pollinating insects in gardens
• Native plants are not always the first choice for pollinators visiting gardens
• Non-native plants can prolong the flowering season providing an additional food source

Surprising results for many!

The basis of a garden’s health and vigor is determined by invertebrates, animals lacking a backbone. The more critters making a home or just stopping by for a refueling visit, the healthier your garden is to the environment and your health and well being.

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Dragonfly on waterlily

 Findings and Messages

For all pollinator groups on all treatments, greater floral resource, either native or non-native, resulted in an increase in visits. There was, however, a greater abundance of total pollinators recorded on native and near-native treatments compared with the exotic plots.

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Allegheny Vine, Adlumia Fungosa, is an endangered North American native, closely related to Bleeding Heart

Exotics were notable in extending the period of bloom which is really important to attract insects all season long.

The takeaway here – use site appropriate native plants when possible, understanding that some are a bit more boisterous than others, but add exotics where appropriate to enrich and extend the season. Gardens can be enhanced as a habitat by planting a variety of flowering plants, tilted towards native and near-native species.

 

The Great Butterfly Bush Debate

Butterfly on butterfly bush bloom
Butterfly on butterfly bush bloom

Butterfly Bush, Buddleia davidii, has been widely bashed from garden writers, ecologists, and conservationists. Attacked from all sides by master gardeners and other garden professionals, I am sticking to my guns on the benefits and pleasures of planting it. “An invasive thug that only provides sugar-water”: That is the complaint that conservationists use to discourage you from planting this shrub.

Swallowtail
Swallowtail

 As a preferred late summer nectar source and butterfly magnet, I enthusiastically promote it in my butterfly presentations for its many virtues. An important tool to draw butterflies, I also plant many natives next to it that can act as host plants.

Swallowtail on bloom
Swallowtail on bloom

One of the few flowering shrubs that deer will not touch, I use it all the time in my landscape designs as an easy to grow, beautiful, fragrant, disease free, flowering shrub. The only care required is a general whacking back of the whole shrub in the early spring to encourage bushiness and flower production. Over 100 varieties provide a wide palette of forms, sizes, and colors, to choose from. The dwarf varieties are especially valuable for small gardens and containers, like ‘Blue Chip’ and ‘Pink Chip’, growing only 4 feet tall.

Butterfly Bush 'Pink Chip'
Butterfly Bush ‘Pink Chip’

Why do butterflies love this plant? Providing loads of sugar water , the nectar filled nectaries, are shallow which is important to accommodate the short-tongued butterfly. Butterflies can reach the copious nectar easily which has a high percentage of sucrose, an energy fuel. Attractive to moths, bees, and other insects, this plant is valuable to all kinds of wildlife, not just butterflies.

Miss Molly Butterfly Bush in border
Miss Molly Butterfly Bush in border
Miss Molly adds a new color, raspberry, to the mix
Miss Molly adds a new color, raspberry, to the mix

Native to Japan and China, butterflies don’t care where their source of nectar hails from. In my post Butterfly Watching, I noted that butterflies have taste receptors on their feet to locate food and if their foot’s receptor and the molecule match, the butterfly eats. So, the plant’s origin is irrelevant and is an attractive food source. As humans, we eat many non-native plants, why can’t a butterfly do the same?

The butterfly bloom nectaries are numerous and easily accessible
The butterfly bloom nectaries are easily accessible

Invasive thug or non-native adaptive? There are several ways of looking at this plant. I know that it invades into mostly disturbed areas where lots of aliens/invasives have already taken over and is known as an invasive in over 25 states. But still, it is providing an important late summer source, when it is sorely needed. The other short-coming that ecologists claim is that butterfly bush only provides nectar, not acting as a host plant for the caterpillar to reproduce, but that is also true of other native plants.

Monarch caterpillar on milkweed
Monarch caterpillar on milkweed

Butterfly Bush seeds do not ripen until dry weather during the following spring. Worried by the potential for invasiveness? Then you can dead head it before the seeds ripen in the spring or cut the whole bush back which will eliminate the spread of seeds into adjacent habitat. Colonizing disturbed ground sites such as railway lines, quarries, roadsides and waste ground, butterfly bush can form dense stands of shrubs that butterflies flock to. What’s not to like!? Here is the position of the UK’s Butterfly Conservation on their website:

“Buddleia provides an important nectar source for adult butterflies, moths and other insects in townscapes and the countryside. This has become increasingly relevant because wildflowers have become so depleted following habitat loss and the general lack of nectar sources in the countryside. It also brings enjoyment to many people, both because of its heavy-scented and beautiful blooms but also because of the butterflies and other insects it attracts. It therefore plays a role, alongside other non-native garden plants, in helping to maintain or restore the link between people and native UK wildlife such as butterflies. In gardens, Buddleia is often pruned annually thus removing seed-heads and reducing the potential for seeding.

Buddleia is not important as a caterpillar food-plant and cannot replace naturally occurring wildflowers, which are crucial to provide a variety of nectar through the year as well as being food-plants for caterpillars. Buddleia can cause serious problems on some important conservation sites, especially brownfield sites. It needs to be controlled in these and other semi-natural sites to allow natural vegetation to develop. The cost of control can sometimes be considerable.

In reaching a position on Buddleia it is important to weigh up the undoubted benefits it brings in garden situations against the possible risks to wildlife habitats. It is also important to recognise that Buddleia is already naturalised and well established across much of the UK.

In view of its value as a nectar source, BC will continue to recommend its planting in gardens alongside other butterfly-friendly non-native plants, but will avoid giving it undue prominence and will give advice on its management and control.

Miss Molly
Miss Molly

A sea change is going on with some conservationists, that we are dealing with a changed world and there is no way to go back to an idealized world of  stable co-habitating species. From the beginning of time, species have moved around, finding new territories, and creating new ecological niches. Invasive species, like it or not, are part of nature. Serving an ecological purpose, whether it aligns with our idea of what it should look like, isn’t relevant to nature.

And according to the Royal Horticultural Society:

• Research reveals a mixture of native and non-native ornamental plants may provide the best resources for pollinating insects in gardens
• Native plants are not always the first choice for pollinators visiting gardens
• Non-native plants can prolong the flowering season providing an additional food source.

So, armed with this knowledge, you make the decision.

Swallowtail on bloom
Swallowtail on bloom

The Worst Garden Trends

I admit with the start of a new year, that I get on a trend kick. Looking back, I see things that are in the negative column, that we as gardeners should not be doing.

Read on to see my take on it. If you want to see things that are up and coming, see my post on 12 top Garden Trends for 2014.

1.Excessive Mulch/Volcanoes

Tree volcano around a holly
Tree volcano around a holly

The practice of piling up mulch around trees and shrubs in the landscape is ubiquitous and I cringe every time I see it. Landscape firms need to take Landscape Planting 101, to learn the detrimental effects that happens to any plant material if you pile layers of mulch around a plant trunk. Rot, insect damage, and small rodent damage is liable to kill this tree above, within a couple of years. And how about the practice of piling too much mulch in a garden, sometimes as much as 4 inches thick, that can smother your plantings? And form an impenetrable crust on top? Rampant in the mid-Atlantic region, mulching excessively is too much of a good thing.

2. Bradford Pears

Uprooted tree
Uprooted tree

I can’t understand why people are still planting this fundamentally flawed tree. Hybridizers claim to have improved cultivars of the Bradford Pear, which are stronger and less likely to break and blow over. I haven’t found that to be the case. Bradford Pears are beautiful when they bloom, but short lived. Stay away from them and choose something as beautiful or better, like a variegated Kousa Dogwood, which also has a plus of great fall color.

Variegated Kousa Dogwood
Variegated Kousa Dogwood

 

3. Patented Plants/Seeds

Cardinal Candy Viburnum
Cardinal Candy Viburnum is a patented plant so you cannot propagate it

Just about every plant developed today has a patent or trademark.  Patents last 20 years,, trademarks into perpetuity. I understand that the plant breeders would like to enjoy some profits from their new varieties, but it is getting excessive, especially with trademarks, since they last forever. It is illegal to propagate a trademarked or patented plant, which makes criminals of many gardeners who love “pass along” plants.

"Pink Marble" Helleborus is a trademarked plant
“Pink Marble” Helleborus is a trademarked plant

Traditionally farmers saved a portion of the seed from their crops to plant the next year or trade with other farmers which is called “farmer’s rights.” However, if there is a patent on the seed a farmer has grown which is very likely nowadays, or it is Genetically Modified seed (GMO), the farmer cannot save the seed to plant the following year. To continue to grow plant patented crops, farmers are often required to sign written contracts stating that they will not save any seed at all. Instead, they must annually purchase their seed from a biotech company or agro business, rather than other farmers or local seed companies. In addition, big agro-businesses are buying up seed companies to control their supplies. Pretty soon, local seed companies will be a thing of the past.

4. TV/Radio Gardening Programs

A little British humor displayed on a sign in the Cotswolds
A little British humor displayed on a sign in the Cotswolds

What ever happened to Victory Gardening? I loved this show but it was really hard to find on my local station, if at all. The dearth of garden related shows in the U.S., both TV and radio is depressing.  Ok, I know about landscape makeovers on HGTV! That show is all hype and no substance. But the British have a great sense of humor and know how to garden.

Listen to what the British public can see: The Edible Garden, The Landscape Man, Garden Question Time, Gardeners World,  and Great British Garden Revival. And if you go to http://www.telegraph.co.uk/culture/tvandradio/tv-and-radio-reviews/10506390/Great-British-Garden-Revival-BBC-Two-review.html, you can see some reviews. These programs offer “sensible advice and lovely shots”. The English always know how to garden well. See “Brilliant“, my post on the Philadelphia Flower Show with a British theme.

Here is my wish list of a gardening TV program. I would like someone to cover things like Mosaiculture, which moves around the world and was recently in Atlanta and Montreal. It is an expression of new millennial values and is a refined horticultural art that involves creating and mounting living artworks made primarily from plants with colorful foliage (generally annuals, and occasionally perennials).

Or cover the gardening revolution with edibles. Here are edibles on the front steps of Parliament Building in Quebec City.

Edible gardening in Quebec City in front of Parliament building
Edible gardening in Quebec City in front of Parliament building

How about a show on gardening trends like the new tomato varieties, “Purple Tomatoes” or the “indigo” varieties, see “Top 12 Garden Trends” for more details.

Purple Power Tomatoes by Mighty 'Mato Grafted Collection
Purple Power Tomatoes by Mighty ‘Mato Grafted Collection

Or, wouldn’t you like to see the artists in action drafting the new seed packet cover illustrations? See “Art of the Seed“.

The topics are endless, but there aren’t any TV or radio shows on gardening in my area.

5.  Garden Snobs

I love garden gnomes!
I love garden gnomes!

You have all met one if you have been on a garden tour or gone to a plant sale. It is the person ( I won’t name names!), who is spouting the Latin names of plants and wouldn’t consider planting a petunia on their property. Annuals is a bad  word and their gardens are full of unique and very expensive plants and statuary. And no, I did not just describe myself! I admit that I do use Latin names, but I only spout them out when I am with garden professionals, and I love annuals and garden gnomes! I won’t deny that I do have a garden of very expensive plants that die all the time, but nothing that I had to mortgage the house for!

Gardening snobs want the latest and greatest plant. They don't care if it fits in with their garden.
Gardening snobs want the latest and greatest plant. They don’t care if it fits in with their garden.

 

6. Invasives 

Get over it! Invasives are here to stay and nothing is going to change that. I get frustrated when I hear about groups arranging slash and burn weekends to remove invasives from designated areas. I say-  Forget. About. It. This is a losing battle and you are just going to go crazy trying to fight it.

Oriental Bittersweet is an invasive that is attractive but taking over the woods
Oriental Bittersweet is an invasive that is attractive but taking over the woods

For example, English Ivy is a rampant growing invasive, brought by the earliest English colonists, choking out native species. Lots of people still grow it, as it does cover the ground in the shade, and is deer resistant. At Princeton University, an “Ivy League”, they pulled it off the brick walls of the buildings to repoint, and then re-attached it! So, what is one man’s meat, is another’s poison. Ivy is still sold at garden centers because people demand it.

Princeton University covered with Ivy
Princeton University covered with Ivy

 

7. New Pests

Have you noticed that there are lots of new pests to bother you, and more prolific poison ivy? That is due to a variety of factors, namely climate change and the globalization of food production. I will quote from Shashi Sharma, an Austrailian plant bio-security scientist. He said at a recent conference that “Globalization of food production and distribution has enhanced potential for pests to disperse to new regions, find new vectors, new hosts, new environments and new opportunities to evolve into damaging species and strains.” Enough said.

Stink Bugs are here to stay
Stink Bugs are here to stay
Poison Ivy
Poison Ivy

 

8. Ultra Pruning

Why do people want ultra tidy and manicured properties?  It seems that the entire property has to be scalped clean, with no wild areas. That means that the field that used to be in the back of the property, that was let go to wildflowers, is cut like turf grass. Or, how about the huge front expanse of lawn in the front that is cut and doused with chemicals periodically?  Let it go! Plant natives, like butterfly weed, rudbeckias, cornflowers, and golden rod. It is a lot less maintenance and the pollinators will flock to it.

Let some areas in your yard to native
Let some areas in your yard to native
Plant Joe Pye Weed and other butterfly friendly plants in your yard
Plant Joe Pye Weed and other butterfly friendly plants in your yard

Pruning should be done regularly, but beware of doing it excessively, or into tidy meatballs! See my post Pruning 101 for tips on managing your pruning.

9. Decline of Honeybees

I hate to say this, but as a beekeeper for over 15 years, I don’t see things improving.  See my post on Colony Collapse Disorder. I think that this trend of declining bee populations is here to stay. For the past couple of years, my bees have struggled and died. I have put a lot of money into starting up new colonies, but I am going into 2014 without any honeybees in my hives. I will try again with new packages and nucs this year, but I don’t see things getting better in the near term. I got my first mason bee habitat this year and will be putting this box up in the spring, trying to attract these native bees instead.

Mason Bee house with tubes
Mason Bee house with tubes

I am also dedicating a portion of my property to planting milkweed, Aesclepias syriaca, the plant that sustains monarch butterflies.

Plant Butterfly Weed or Milk Weed for Butterfly populations
Plant Butterfly Weed or Milk Weed for Butterfly populations

 

10. Rollout of Plant Varieties that Stink

Stick to the old classics like Agastache Blue Wonder which butterflies and bees love
Stick to the old classics like Agastache Blue Wonder which butterflies and bees love

Do we really need another Heuchera (Coral Bell) that looks great in the pot, costs a small fortune, has a snazzy name, like “Red Velvet Ambrosia”? But the instant you put it in the ground, it sulks, and then dies? Or, maybe it looks good for a season, but come winter, you find that that the plant is not hardy as stated? Remember, ‘Limerock Ruby’ Coreopsis??  The hype that is attached to a plant sometimes is so premature and over stated, that I look at every introduction with a jaundiced eye. I have had more Echinaceas die on me than I have Carter has Liver Pills! Remember, my rant earlier in this post about patented plants? It seems like the patented plants are put on the market before they are fully tested!

Lavender Phenomenal- This is a new variety that has a lot of hype attached and I planted it last season to see how it does
Lavender Phenomenal- This is a new variety that has a lot of hype attached and I planted it last season to see how it does

Lavender ‘Phenomenal’ is a plant that comes highly recommended as a lavender that tolerates our wet winters and humid summers. Normally I treat lavenders as very short-lived plants, here in the mid-Atlantic region of the U.S. But, I am giving this a try and was pleased with it last summer, as the flowers branched off the main stem to form new flowers, which is unique in lavender plants. But I have to see how it weathers this winter which is turning out to be very cold and wet. Before I stand behind a plant, I have to grow it for 3 to 5 years, and I suspect growers who introduce these new plants, don’t give them enough time as well as trying them in different parts of the country.

I stand behind this variety, African Blue Basil. It is a stellar performer, great for pesto and pollinators, and beautiful
I stand behind this variety, African Blue Basil. It is a stellar performer, great for pesto and pollinators, and beautiful

I periodically showcase varieties of plants that I have luck with, can take neglect, are pollinator friendly, and are foolproof. See African Blue Basil or Monkshood, Deadly BeautyButterfly and Bee Magnet, Joe Pye Weed, or Autumn All Stars.

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