by Chris Earley

Happy 150th Canada! And how does an Arboretum celebrate this momentous occasion? Why a maple quiz, of course! The maple is our national tree and there are ten species and one natural hybrid native to Canada. Can you figure out these nine? The answers are at the bottom of the newsletter and a printable version is available at: http://www.uoguelph.ca/arboretum/Listservnewsletter/June_2017/printable_quiz_maple_Canada_150_June_2017.pdf.

May and June are such busy months that it is hard to write about everything, but here are some highlights of what is to come and what has happened here at The Arboretum.

It is almost Canada's 150th Birthday and the garden community in Guelph is celebrating a little early. Garden Day is this Friday, June 16 and you have an opportunity to celebrate both gardens and Canada's 150 with tours of Riverside Park's Floral Clock, our (Arboretum's) World of Trees and the Conservatory Gardens here at the University of Guelph. The event runs from 10 a.m. - 2 p.m. Shuttles are available by registering at: bit.ly/GardenDays2017UG. Further details are on the poster below.

At the end of May we offered a Stone Wall Building workshop. It ran over a weekend for two full days and from all accounts was an amazing experience. Two of our staff Polly and Kellen participated. The weather thankfully co-operated. The wall that was built is outside our Gosling Wildlife Garden for visitors to see. More photos and information can be seen on the instructor John Shaw-Rimmington's blog at: https://thinking-stoneman.blogspot.ca/2017/05/the-university-of-guelph-arboretum.html.

           
            Polly and Kellen with the completed wall.

Our trail system through the Wall Custance Memorial Grove is getting a "facelift." Heavy equipment began working earlier this week to start the process of rehabilitating the trail system in the Memorial Grove. This is thanks to generous donations received for the project. Watch as this project unfolds over the summer months.

            

Our grounds crew is busy this time of the year with both regular maintenance as well as their many projects. Each week our staff are assisted by volunteers in our various volunteer groups. The grounds wouldn't look as groomed and cared for as they do without the assistance of these caring volunteers. If you are interested or know someone who might be interested in assisting with the care of our grounds please contact our volunteer co-ordinator Barb Watson - Ash at [log in to unmask] or 519-824-4120 ext. 52358. An application can be found on our website at: https://www.uoguelph.ca/arboretum/sites/uoguelph.ca.arboretum/files/public/Volunteer_Application_Form_February_2016.pdf

Our interpretive staff are busy with their programs for school and youth groups as well as their Wednesday walks. This past weekend was Alumni Weekend here at the University and Shelley our director led tours for the visiting alumni. The weekends are busy with weddings that take place here and the Arboretum Centre is host to many meetings and conferences at this time of the year.

We hope to see you soon enjoying all The Arboretum has to offer.

by Aron Fazekas

This past year we were fortunate to have a group of 4th year students from the School of Environmental Sciences work on a project for The Arboretum. The motivation for the project stemmed from some conflicting statements that we had seen regarding the level of invasiveness of Norway maple. Norway maple is a non-native tree that has been widely planted in urban areas, but the general understanding is that most (if not all) of the cultivars are potentially invasive. Despite this, it remains a popular tree with growers and landscapers – often to the exclusion of a number of native species that could be used in its stead. As I looked at some of the more recently published scientific literature it became apparent that some of the confusion is due to the recent introduction of some cultivars that produce less seed – and the resulting claim that goes along with them - that they won’t be invasive. The 4th year students provided us with a comprehensive literature review on Norway maple and the results of a survey that they sent to over 40 nurseries and growers in South-western Ontario.

Norway maple was introduced to North America as an ornamental tree in the mid 1700’s. They are relatively easy to propagate, are able to survive in very poor soil conditions and are largely resilient to the stresses of urban environments. They became a popular choice as street trees to replace American Elms that were being affected by Dutch elm disease, and many Guelph neighbourhoods that were developed in the 1950’s and 60’s were planted with Norway maple. They continue to be widely planted today with several cultivars available. Most cultivars produce copious amount of seed, some of which inevitably ends up in natural systems. The same characteristics that make these trees successful in urban environments have consequently led to their naturalization in local woodlots or forests. However, as Norway maples grow they have a significant effect on the establishment and growth of native tree species. Norway maples typically have a very dense canopy. In the city this can result in thin patchy grass under a mature tree, but in a natural area it means that native trees have difficulty germinating and grow much slower than they otherwise would. This inhibited growth seems to apply only to native species – seedlings of Norway maples seem to be unaffected when grown under mature Norway maples. There is also some evidence that the Norway maples may produce chemicals that accumulate in the soil that inhibit growth of native species, and they also seem to be much less affected by insects than native maples. Due to these traits, some U.S. states have formally classified Norway maple as an invasive species and/or banned it for sale.

In Ontario, however, it is still readily available and the students working on the project were interested in some of the opinions of the people growing and selling these trees. The survey indicated that for the most part the main appeal of Norway maples over native maples is the deep red foliage of some of the cultivars and the shape or form of the tree. Two thirds of respondents also indicated that Norway maples are preferred because they have better overall performance and survivorship, and can be planted in locations where other species will not last. In general most growers seemed aware of some of the issues with invasiveness, but some felt that this was due to overplanting of this species, and others that the issue has been exaggerated. Certainly, some growers have noticed a shift in demand recently and are responding with greater availability of sugar and red maple as well as other native species.

While Norway maple is a significant problem in parts of the Northeastern United States, some recent work has suggested that it may not be as significant of an issue yet in Ontario. The use of Norway maple has a longer history south of the border so it may be that we have not used it for long enough or as frequently to see the same level of impact. It’s not too often that we get the chance to avoid potential problems with invasive species, but this may be one. As knowledge about the potential invasiveness of Norway maple (and other species) spreads to the public and municipalities, consumer demand may continue to push a shift towards a greater proportion of native trees being planted. The current lists of urban tolerant trees for the city of Guelph for example are almost entirely native species – Hackberry, Ironwood, Bur Oak, etc. (http://guelph.ca/living/house-and-home/healthy-landscapes/landscape-planning/plant/). While it’s probably true that some of these species won’t survive long in the compacted earth associated with construction of roads and buildings, taking the time to properly amend the soil to support native species is worth the effort.

This fall we hope to collect seed from some of the Norway maple cultivars as well as from some of the native maples in The Arboretum collection. With seed in hand we will be able to establish some trials that can help fill in the gaps in our knowledge about how these species interact under different conditions – and whether or not some of the newer cultivars that produce less seed will actually be beneficial – or whether their offspring will revert to a normal level of seed production. With more information about how non-native species such as Norway maple interact with our natural systems we will be better equipped to predict and react to potentially undesirable consequences.

The Arboretum thanks 4th year students Alexander Drake, Caitlin Fortune, Jacob Goulet, Julian Lum and Rachel Vandenbroek for their work on Norway maple this past year.

A printable / sharable version of this article is available at: http://www.uoguelph.ca/arboretum/Listservnewsletter/June_2017/Norway_Maple_Aron_June_2017.pdf

by Jason Chan

flowering blooms on an Ohio Buckeye

If you’ve taken a stroll through The Arboretum lately, you may have heard the bees buzzing and have seen the butterflies fluttering because many plants, shrubs and trees are flowering. On our Wednesday Noon Hour Walk two weeks ago, we walked by the Ohio Buckeye (Aesculus glabra) and we found that some flowers in bloom were yellow and some were red/pink. Shortly after, we came across the Yellowhorn (Xanthoceras sorbifolium) and again noticed the same phenomenon. wracking my brain, I remembered that the flowers of the Horse Chestnut (Aesculus hippocastanum) are known to change color after being pollinated - perhaps this was the phenomenon we were observing! Though it’s quite the interesting fact, a bit more thought led to a slew of questions; what is the mechanism behind the colour changes we see? Is it really triggered by a pollinator’s visit? What other flowers change colour? Why those colours in particular? What adaptive or functional purposes come with changing colours?

According to my research, there are currently over 70 families of flowering plants that are found to change colour and there have only been a handful of studies that have investigated why flowers change colour and their relationship with pollinators. Some plants with colour changing flowers that can be found here at The Arboretum include Lungwort, Forget-me-nots, Lupines, White Trilliums as well as the Ohio Buckeye, the Yellowhorn and the Horse Chestnut as mentioned.

Why do the colours change?
The mechanisms behind these colour changes are due to different pigments, namely anthocyanins, carotenoids (which is the colour we see in carrots) and betalains. Studies have found that the changes in colour, which usually go from a lighter colour, such as a white or yellow, to a darker colour like purple or red, could be dependent on the surrounding temperature, changes in the acidity (pH) of the plant or in the soil, aging, stress and also exposure to light. But is it ever directly triggered by a pollinator’s visit? One scientific article suggests that pollination appeared to cause a chain reaction that would lead to the reddening in the genus Lupinus. But overall, most studies have not directly attributed the color change in most flowers to a pollination event. We may have many different hypotheses and guesses when it comes to understanding the colour changes in certain flowering plants, but it’s all still quite a mystery!

So what about the pollinators?

Whilst the exact trigger of floral colour change remains unknown, research has tried to explain the functional aspect of these colour changes, and much of it is suspected to do with the pollinators. For one, the colour change is thought to be a ‘nectar guide’; a visual indicator of which flowers have a greater nectar reward. Lighter coloured flowers, which are usually the younger flowers, are found to have more nectar and therefore insects may learn to discriminate between the two colours. Not only that, but some flowering plants such as the horse chestnut have “candles” which are the large pyramidal flowering structures (see image). Scientists think that these large visible structures are used to attract pollinators from a distance before they see the localized colour changes on the flower. By attracting pollinators, it is a win-win situation; the tree gets pollinated and the pollinators receive nectar. It has also been observed that in the Horse Chestnut, the odour of the flower also changes with the colour which is an added advantage, catering towards how some insects, especially beetles, discriminate flowers by their sense of smell.

We often walk by trees and shrubs without really knowing what they are really up to. I encourage you to take a look at some of these unique plants that have colour changing flowers the next time you come for a walk. “But The Arboretum is huge! How will I find them”? one may say. Not to fear, let me introduce you to Arboretum Explorer, an online interactive database that helps you locate the shrubs and trees we have in our collections here on our grounds! Simply follow this link; https://guelph.arboretumexplorer.org/, enter in the common / scientific name of the tree you want to find and watch for the yellow circle that reveals the location of the desired tree/shrub on the map! If you’re on the grounds, be sure to take advantage of Arboretum Explorer!



A printable / sharable version of this article is available at: http://www.uoguelph.ca/arboretum/Listservnewsletter/June_2017/Colour_Changing_Flowers_Article_Jason.pdf

References:

Shimokawa. S. (2015). Biochemical mechanism of flower color changes and thei reffects on
pollinators in Weigela (Caprifoliaceae) and Hibiscus (Malvaceae). Tokyo Metropolitan University.

Weiss. M.R. (1995). Floral color change: a widespread functional convergence. American Journal
of Botany. 82(2):167-185

Weiss, M.R., and Lamont, B.B. 1997. Floral color change and insect pollination: a dynamic
relationship. Israel Journal of Plant Sciences. 45:185-199.

http://www.hiddenvalleyhibiscus.com/misc/colors.htm
https://www.thestar.com/news/insight/2012/06/02/amid_sea_of_white_trilliums_one_is_pretty_in_pink.html

We have two great options available for guided walks on The Arboretum grounds.

Join Jason every Wednesday at 12:15 as he explores the grounds on a 50 minute hike. It is a wonderful way to explore as spring migrants return and life blooms on The Arboretum grounds. The walk is free and you should meet at the kiosk at the end of the promenade closest to campus if you are interested in participating.

On Wednesday evenings through to the end of August our Summer Interpretive Naturalist, Rachel leads our Wednesday Evening Walk series. These programs take place each Wednesday evening from 7 p.m. - 8:30 p.m. beginning at the J.C. Taylor Centre. The cost is $2 per person with children under 5 free. Here are some of the upcoming walks:

Nature Art (June 21) - Nature is constantly changing and that is something Andy Goldsworthy captures in each of his creations. Using only natural materials he creates sculptures and art within different landscapes that overtime change, decay and disappear - just like all of Mother Nature’s masterpieces. This Wednesday, come channel your inner Andy Goldsworthy and let the forest be your canvas. We will be using materials found throughout The Arboretum to create temporary nature inspired masterpieces. No art background is required!

Whose Nose Knows (June 28) - There are a lot of scents that we associate with summer: the pleasant, earthy smell after rain, fresh cut grass, blooming lilacs, and sunscreen lotion. The human nose can detect one trillion different odours - the nose knows more than we think! Come join us as we get nose-y and investigate the different ways that animals smell the world.

This is the popular time of the year to get married. We have two picturesque outdoor ceremony sites as well as indoor space with a fabulous view for wedding receptions. If you or someone you know is looking for a space for your wedding ceremony and / or reception please contact Dawn Ann Webster at 519-824-4120 ext. 54110 or [log in to unmask]. Further information on our unique reception facilities and outdoor ceremony sites can be found on our website.

 
West Lawn                                        Auditorium

The Arboretum’s grounds are the perfect setting for group tours. Our knowledgeable docents (trained volunteer guides) give pre-arranged 1 ½ hour tours of The Arboretum’s grounds, gardens, collections and other points of interest. The tours can be focused on the areas that are seasonally appropriate and / or that are of interest to you and your group. Tours should be booked a minimum of 2 weeks in advance. The cost is $5 per person, with a minimum charge of $60. Tours provide an excellent break for a meeting group. For further information on tours or to make a reservation please contact Dawn Ann Webster at [log in to unmask] or 519-824-4120 ext. 54110.

Did you know that The Arboretum makes the University of Guelph campus one of the most biodiverse university campuses in Canada? This year we are doing our bioblitz during the week to see if more people can come out from our campus population. No experience necessary - just come and learn! If you have experience, you can come and lead! Details: Friday, June 23. Meet at the J.C. Taylor Nature Centre at 9 am. We will do a short intro and then everyone can break off into groups and go out and survey! We won't be doing any formal hikes but there will be focus groups that we can set up before everyone goes out. We will have binoculars, nets, vials and field guides available. We will finish up at 4 pm. If you are staying for the whole day, be sure to pack a lunch!  For further information please contact Chris Earley at [log in to unmask] or ext. 52201.

Guelph Bug Day is a fun, free, educational event for community members of all ages. Our goal is to cultivate a fascination for the very cool, very small world of insects! Come get up close and personal with our live specimens, take one (or two, or three!) guided bug-catching hikes in the expansive and beautiful grounds at the University of Guelph Arboretum, try tasty insect cuisine, put your imagination to the test with insect drawing contests, and explore the variety of buggy vendors that Guelph has to offer. Rain or shine, bring your adventuring spirit and prepare to be amazed.

Follow us on Twitter @GuelphBugDay or on Facebook "Guelph Bug Day"

Butterfly, Dragonfly and Damselfly, Shrub Identification, Tree Identification, Shorebirds and Smartphone Photography workshops are approaching. The dates and registration deadlines can be found in our Coming Events listing in the column on the left side of this newsletter. A detailed description of each course is available on our website. Help us promote our programs… please forward this e-mail on to your friends and colleagues who may be interested. The more participants we have, the more programs we can offer.

Late May and early June are busy wildlife sighting months here at The Arboretum. Recently, we have seen a newly emerged baby Painted Turtle, our first-of-the-year Giant Swallowtail, the return of the Monarch butterflies, a Porcupine, a White-tailed Deer, singing American Redstarts, baby mallards, aphids giving birth and a really big Bold Jumping Spider. We have found many bird nests including those of a Yellow Warbler, a Cooper's Hawk, a Great Crested Flycatcher and an Eastern Phoebe. Blooming trees include Cucumber Tree, Tulip Tree, some late-flowering lilacs and Horse Chestnuts. And some fruits are appearing, too, including our serviceberries just outside of The Arboretum Centre which are attracting a large number of Cedar Waxwings. Come and see them!

 
Cucumber Magnolia                            Tulip Tree
photo by Brenda Doherty                     photo by Brenda Doherty

 
Giant Swallowtail on Lilac                     baby Painted Turtle
photo by Brenda Doherty                    photo by Chrid Earley

Be a part of the BetterPlanet Project by donating on-line:

Your donation can be directed to The Arboretum online through the secure University of Guelph donation page: http://uofg.convio.net/arboretum

If you prefer not to make an online donation, there are several other ways to provide your financial support. You can choose to donate by telephone, mail, fax, or in person:

UNIVERSITY OF GUELPH Attention Alumni Affairs 50 Stone Road East Guelph, Ontario, Canada N1G 2W1 Tel: 1-888-266-3108 ext. 56934 Tel: 519-824-4120 ext. 56934 Fax: 519-822-2670 Email: [log in to unmask]

If you would like information on bequests and planned giving to The Arboretum please contact:

Amy Atkinson
Senior Development Manager, Ontario Agricultural College
at (519) 824-4120 ext. 58652 or by e-mail at [log in to unmask]