All posts by peterboroughmastergardeners

Native Plant Gardening for Birds, Bees & Butterflies

by MJ Parker, Master Gardener

I recently downloaded “Native Plant Gardening for Birds, Bees & Butterflies” from my local library. This book was a fabulous find for me because I am currently planning a buffer area by the water in our new place. Going through this book reminded me of when I was a kid with a new Sears or Eaton’s catalogue – always an exciting event – something only people of a certain age will remember.

Book cover

The book was written by an entomologist, Jaret C. Daniels, currently living in Florida but the area covered by the book is the upper Midwest which is roughly parallel to us here. I have ordered plants from Minnesota before with no problems and some of the plants I currently grow are in the book.About 1/4 of the book is devoted to why we should plant gardens for birds, bees and butterflies. He does a brief summary on a number of topics about the actual mechanics.

False Indigo (Baptisia australis)

Most of the book, however, was a precis of individual plants roughly divided into sun, shade, and bog. Each plant started with a picture, then a summary of what it would attract and ended with specific location and cultivar tips. And this plant section was the part that I found extremely interesting and helpful.

New Jersey Tea (Ceanothus americanus)

So what I did was I sat down with a pen and paper over a number of days and compiled a list of what would work for me and plants I wanted to get. I ended up with a comprehensive list of plants, some I had forgotten to bring from the old place and some completely new to me.

And to date I have already placed 2 seed orders for some of the things on my list.

Insect Galls on Trees

By Laura Gardner, Master Gardener in Training

I was out for a walk earlier this summer and noticed that a number of trees in my neighbourhood have lumps on their leaves, leaf stalks, shoots, or at the ends of their branches. At first glance you might be alarmed and think they are diseased, but many are the homes of tiny insects such as aphids, mites, sawflies, psyllids, and midges. They are often quite numerous and they come in different shapes and sizes. A gall is formed through the expansion of plant cells—similar to a tumour. This may be triggered by organisms such as viruses, bacteria, fungi, nematodes, or insects. Insects induce the galls through actions such as oviposition (inserting the egg into the plant tissue), the release of chemicals by the female and eggs, and through feeding. It is a shelter for the young and protects them from predators. While sometimes causing leaf deformity, in the majority of cases, galls are a cosmetic concern and do not harm the tree.

Here are a few you may encounter that are caused by insects:

These variable shaped galls specific to Populus deltoids (Eastern cottonwood) are the homes of an aphid called Mordwilkoja vagabunda (Poplar Vagabond Aphid). New galls are a light colour but become darker with age. Each gall releases upwards of 2,000-winged offspring in mid-July to early August. Sounds like it could have been the inspiration for a science fiction novel or movie.

Rabdophaga strobiloides (Willow Pinecone Gall Midge) are found at the ends of branches of various Salix spp. (Willow). What is amazing about these structures is that up to 31 different insects use them for their young—residing in the papery-like folds of the gall.[i] The galls are also frequently predated by birds and parasitic wasps.[ii] The biodiversity that Willows support is wide and for this they are known to be keystone species—they are also among the earliest plants to flower in the spring and support emerging pollinators like Queen Bumblebees.

Euura proxima (Willow Redgall Sawfly) frequents certain Salix spp. (Willow). This gall can be identified by its red bean-like appearance on the leaves. Sawfly larvae are often mistaken for Butterfly or Moth caterpillars. They can be distinguished by the number of abdominal prolegs: the former has six or more and the latter five or less.

Pachypsylla celtidismamma (Hackberry Nipple Gall Maker) is a Psyllid (Jumping Plant Lice) that forms round, often clustered galls on the underside of Celtis (Hackberry) trees. Adults spend the winter in cracks of the tree bark itself or even in nearby buildings.

The Eriophyid mite, Vasates quadripedes (Maple Bladder Gall) forms on Acer spp (Maple) such as the upper leaves of this Acer x freemanii ‘Autumn Blaze’ (Freeman Maple ‘Autumn Blaze’). The galls first appear as green, then turn to red, and finally black. The mites overwinter in the creases of the tree’s bark.

So, if your trees have strange growths on them, check out the wonderful web site https://gallformers.org. There you can identify galls by their specific host trees, the form of the galls, and their location on the trees. You can also narrow your search down to those that occur in Ontario. Another good site for identification is https://www.bugguide.net, a comprehensive database of insects for the US and Canada.


[i] Willow Pinecone Gall Midge. Minnesota Seasons. http://www.minnesotaseasons.com/Insects/willow_pinecone_gall_midge.html#:~:text=It%20consists%20of%20numerous%2C%20stunted,shape%20resembles%20a%20pine%20cone

[ii] Van Hezewijk, B.H. and Roland, J. (2003), Gall size determines the structure of the Rabdophaga strobiloides host–parasitoid community. Ecological Entomology, 28: 593-603. https://doi.org/10.1046/j.1365-2311.2003.00553.x

Jumping Worms & Invasive Species Awareness

By Christine Freeburn, Master Gardener

Master Gardeners have been talking about the importance of controlling invasive species for years. Purple Loosestrife, Giant Hogweed, Buckthorn, Garlic Mustard and Dog-strangling Vine are on a long list of Invasive Plant Species.

You can check the list out at www.invasivespeciescentre.ca  or www.invadingspecies.com

But there are more than just invasive plants. There are also invasive insects like Spongy Moths and Emerald Ash Borer. There are invasive fish and invertebrates like Zebra Mussels and Asian Carp. We have invasive pathogens like Dutch Elm disease (Dutch Ed: “Identified by the Dutch, not CAUSED by the Dutch”). And just recently, we have begun to hear about Wild Pigs and Jumping Worms.

I took part in a webinar presented by the Royal Botanical Gardens on Jumping Worms (JWs) earlier this month. Two speakers, Brook Schryer from the OFAH who works with the Invading Species Awareness Program and Dr. Michael McTavish with the Smith Forest Health, University of Toronto, spoke about the need to be aware of jumping worm sightings in Ontario. They gave information about Eddmaps.org where interested citizens can share their own findings. You can find a recording of this event at https://www.youtube.com/user/royalbotanicalgarden

Now is a good time to find JWs as they are adults at this time of year and can be better identified.

Jumping Worms are an invasive species of Asian worm that are slowly moving their way from the United States. They are voracious eaters and can consume much of the compost, topsoil and debris that lays on forest floors. They leave behind worms castings that are loose and crumbly similar in appearance to coffee grounds. They are often found in wet and shady spots and castings are spread evenly rather than in clumping piles. The castings can be a thin layer or can be 10 cm deep. It will appear as though the ground has been previously dug as the soil will be loose. Jumping worms are distinguished by their thrashing behaviour when moved or picked up. They have also been known to amputate their tails as a method of evasion from predators. There are usually many worms found together close to the soil surface. The worm body is smoother than our earthworm and tends to be more gray than red. The milking band or clitellum goes all the way around their body. Although the worm dies in the cold winter months, their cocoons survive, becoming juvenile worms in May and June and adults in July.

Left on their own, these worms can spread up to 10 meters per year. However, without human help, the spread could happen much quicker.

Research in Canada is happening, but we should all be aware of the dangers of this invasive species, and take precautions.  We just need to think of the days before Phragmites showed up in every wetland and ditch in our area. Awareness and education are important.

Check out the EDDmaps.org site where you can see where actually sightings of invasives have been recorded. The two presenters encouraged us to go out and search for signs of the Jumping Worm and report it to the EDDmaps, whether a positive sighting or a negative one. You can also call the Invading Species Hotline at 1-800-563-7711 if you have a concern.

Google Lens (free!) for all of your identification needs

By Mary-Jane Pilgrim, Master Gardener

If you’re outside enjoying the fresh air, and happen across a flower or bird or insect and you’re not sure what you’re looking at, a new feature from Google can help you out.

Google Lens lets you search what you see. Using a photo, your camera or almost any image, Lens helps you discover visually similar images and related content, gathering results from all over the internet.

All you need to do is: On your phone, open the Google app and in the search bar, tap Google Lens. Point your camera at the flower to identify the plant. Swipe up to learn about the discovery.

On Android, Google Lens is likely already built right in — open the Google App or Google Photos app. Tap Discover or tap the Google Lens icon.

On Apple, Google Lens is part of the Google app — a separate app from using Google on Chrome, Firefox or Safari. Go to the App Store and download/install Google as a unique app if you haven’t already done so.

When you open the Google App, you’ll see a screen like this with the Lens icon. It’s your window to discovery!

Last week, I went for a long walk and checked out a lot of the volunteer trees and plants along the rural roadway. Sometimes I wanted to verify an item I thought I already knew, but more often I wanted to determine the name of a common but name-unknown item. Google Lens scored on both fronts. Now if only I could remember all of those names!

If you have a bug infestation, use Google Lens to identify the bug if you can get it to sit still long enough!

There’s plenty more you can do with Google Lens, too, including pulling the contact information from business cards, identifying unusual foods and almost anything else. It can also translate words on the screen into other languages, and read them back to you.

The ability of the app to actually CORRECTLY identify plants and bugs is pretty decent, and will get better over time. It helps to allow Google to use location services, so that it’s not searching through the entire rain forest to determine the name of the plant in your neighbourhood. You can also allow Lens access to your photos, so that you can identify items you’ve already taken pictures of.

Best of all, it’s free and will always be free. Try it!

The Golden Glow Has Got To Go

By Emma Murphy, Master Gardener

Last year around this time I wrote a blog about reclaiming a garden bed from the dreaded ditch lily (Hemerocallis fulva), now considered an invasive species by many organizations including Ontario Parks and the US Fish & Wildlife Service and the U. S. National Park Service. If you’ve ever struggled with this plant you know what I mean.

The other plant growing in our large Lakefield garden when we moved in (more than 20 years ago) is what I was told was called an ‘outhouse plant‘. I eventually learned that the Latin name for this plant (also called golden glow or tall coneflower) was Rudbeckia laciniata “Hortensia”.

Rudbeckia laciniata “Hortensia” or Outhouse Plant, circa 2005 in my garden

It’s a cultivar of our native Rudbeckia laciniata, also known as Cut Leaf Coneflower or Green Headed Coneflower, which has a lovely simple daisylike flower (whereas the Hortesia cultivar is a double ‘puffy’ flower).

Our lovely R. laciniata elsewhere in the garden. It will do better (and flop less) if it’s in a garden bed with other tall and native plants.

The outhouse plant was pleasant enough so I let them grow for years in what I call our ‘back 40’, meaning our naturalized garden area at the back of the property, behind the cedar rail fence. Yes they were tall and gangly, and fell over in thunderstorms. Yes they spread, but they gave the prolific Canada Goldenrod (Solidago canadensis) and New England Asters (Symphyotrichum novae-angliae) a run for their money in August/September. And hey, I had more than enough to deal with in the rest of my more organized garden!

However, as I started to learn more about both native (and invasive) plants over the years I realized that I might have a problem. The outhouse plant isn’t a huge problem per se, as it can be controlled through digging, Chelsea chop etc., but its double shape means that it offers minimal benefit as food for our pollinators. And I wanted plants that not only look beautiful but have an ecological benefit. So I sat in my hammock and pondered.

Sitting in my hammock contemplating the outhouse plant’s fate
(he’s watching on the right)

As a result of winter sowing (first time this past winter – highly recommend!) I have lots of new native plant seedlings, including some of the ones I featured in my May blog – A Few of My Favourite Native Plants – Culver’s Root (Veronicastrum Virginicum), Cardinal Flower (Lobelia cardinalis), and Green Headed Coneflower (Rudbeckia laciniata). I certainly have lots of the native Rudbeckia, as well as Boneset (Eupatorium perfoliatum), Giant Ironweed (Vernonia gigantea), and Purple Giant Hyssop (Agastache scrophulariifolia).

So the clearing of the outhouse plant began in earnest last week, and by the end of two afternoons I had an area to work with.

The initial chop of material
Then removal of the actual plants and roots

Definitely not light work, but not too difficult either compared to other plants. The area is now clear, and I’ll be putting in Green Headed Coneflower (the native), Boneset, Giant Ironweed, and Purple Giant Hyssop. They can all tolerate a little competition (a good thing for native plants, especially tall ones) and basic soils.

If I have space I might even mix in some shorter plants like native Bush honeysuckle (Diervilla lonicera) and Pearly Everlasting (Anaphalis margaritacea) in at the front as they can tolerate dry conditions. The area is mostly sunny all day. Unfortunately my beloved Cardinal Flower and Turtlehead are too dry for this location.

We’ll see how this experiment works and check back in with you all on another blog. If it works we’ll expand into another area of outhouse plant that I recently cut down, but haven’t removed yet…a work in progress. There are only so many hours in my (still working part time) day. And I still need to get that Canada Ggoldenrod under control…but that’s another story…

Naked Ladies in my Garden

By Lois Scott, Master Gardener

Although this may sound shocking to some and possibly enticing to others, the Naked Ladies in my garden are a welcome arrival at this time of year.  It is not so much that they are truly naked, they are just minus their leaves.  Naked Ladies, Autumn Crocus and Meadow Saffron are all common names for a bulb-like corm called Colchicum autumnale that produces leaves in the spring and flowers in the fall.  Over the summer the plant appears dormant but by late August or early September it starts pushing up beautiful mauve flowers with 6 showy stamens, all atop white stems.  Colchicum autumnale likes organically rich, well-drained soil and sun to part shade conditions. https://onrockgarden.com/index.php/plant-of-the-month?view=article&id=92:colchicum-autumnale&catid=22

This is a sentimental plant for me as years ago I dug up the corms from my grandparents’ garden.  I remember they were still a mass of blooms at Thanksgiving.  But as much as they mean to me, they can be a garden design challenge.  The leaves that are produced in spring grow a good 25-30 cm and then go through a bit of a collapse as they die off.  At that point you are left with a hole.  The flowers grow to be about 15-20 cm tall and could easily be overwhelmed by larger plants around them.  I have my most favourite site for them at the base of a Witchhazel shrub which is close to a garden bed edge. There are a few rocks surrounding the area where the plants are sited and otherwise, I leave the area bare.  The photo I have included is a previous arrangement but I found the leaves in spring overwhelmed the Heuchera, so the heuchera have been moved out a bit.  The other photo shows the leaves in spring.

Colchicum autumnale in fall

You may find corms for sale in the fall or perhaps you know someone who wants to divide up their clump.  They can easily be divided every few years and speaking for myself, I am happy to share.  The ladies in my garden are trouble free and never disappoint.

Colchicum autumnale in spring

My Newest Favourite Flower

By Marilyn Homewood, Master Gardener

One of the new plants that I tried this year was Lisianthus (Eustoma grandiflorum) also known as prairie gentian.  Lisianthus are flowering plants native to northern Mexico and the Great Plains in the United States and as with most prairie plants, they love the heat and are quite drought tolerant.  I thought they just might work in my growing conditions.  The plants are hardy in USDA zones 8 to 10 and are grown as annuals here in Ontario.  Their flowers come in a wide range of colours, are double or single, can be very ruffled and are reminiscent of a rose.  They produce multiple buds on a single stem and one stem can bloom over a 3 week period.  A single stem will last around 2 weeks or more in a vase.  Plants bloom around late July/August and if pruned back when finished, a second smaller flush should bloom in September.  What a treat in August when almost everything else is flagging in the summer heat to have this beauty bloom! A welcome sight in that period before the dahlias really get going.

Is there a down side?  Lisianthus has a bit of a reputation of being difficult to grow. They are very slow to germinate and grow.  Here in Ontario, seeds should be started in early January. I can’t speak to that personally as I was able to purchase plugs in April in order to give the plants a try.  I will attempt to start seed this winter.  There are Lisianthus seed starter groups on line where lots of information and assistance.

Note that these blooms had been in this pot for 2 weeks when the photo was taken!

Seed/Variety Selection

Lisianthus produce tiny seeds hence most of the seed that you purchase is coated to make handling easier (NB coated seed does not store well from season to season).  A number of different series are available and varieties of lisianthus are grouped by bloom season (similar idea to the classifications of snapdragons).  Flowering is stimulated by three factors; Temperature (warmer temperatures accelerate flowering),Light intensity (high light intensity accelerates flowering), and Day length (long days accelerate flowering). By using varieties from Group 2 and Group 3 you can have blooms over a longer period of time as they have different bloom periods.

Cultural Requirements

Lisianthus is a heat-loving plant but it doesn’t like direct afternoon sun. Ideally it should have full morning sun and part shade in the afternoon. The lowest temperature lisianthus can survive outdoors is -12°C and many growers feel that the plant benefits from being planted out before the last frost in order to get their roots established. Lisianthus prefers to have an even amount of water on a regular basis. If it doesn’t rain often, the plant will need to be watered for the best performance.  I neglected to do this (got busy with dahlia issues) and the lack of water was reflected in stem length and bud count but the flowers seemed unaffected (I still had 5-6 buds on each stem). The blooms were wonderful. Recently I visited someone who had watered their plants: they were twice as tall and had even more buds than mine.  Lisianthus can be subject to botrytis hence it’s important to water at the base of the plant. Well-draining soil with a neutral to slightly alkaline pH is preferred. These plants are happy with a feed of compost and if you’re feeling keen, the occasion feed of fish fertilizer. 

Next years seed starting should prove interesting.  Of course, if it doesn’t work there are always plugs!

“Before the seed there comes the thought of bloom” E.B. White

Resources

Armitage, A.M. and J.M. Laushman. 2003. Specialty Cut Flowers, 2nd Edition. Timber Press, 586 pp. 

Lisianthus Seed Starters Group, https://www.facebook.com/groups/198146460815037

Think Spring!

By Cheryl Harrison, Master Gardener

At this time of year, it is difficult to get excited about spring when we know what must come first … fall then winter!  However, late summer is exactly the time to think about spring bulbs because they must be planted in the fall in order to bloom the following spring.

As with all plants, you need to take into consideration the amount of light needed, soil and moisture requirements.  Most bulbs require full sun to part shade, well drained loam soil and watering when dry.  Note that bulbs may rot when over-watered. 

Some sources suggest adding bone meal to the planting hole.  Bone meal adds phosphorus to the soil which may encourage bulb growth but may also harm some of the other beneficial soil constituents.  It is prudent to test your soil first. 

Plant bulbs with the pointed end up and to a depth of 2-3 times the diameter of the bulb.  You may sprinkle blood meal over the planting site or cover with chicken wire to discourage squirrels and chipmunks from digging them up.

Plant your spring flowering bulbs any time between September to December … as long as you are still able to work the ground. 

Spring flowering bulbs are lovely in a formal garden as well as in more natural settings. For naturalization of spring bulbs, please see Bulbs for Naturalizing.

Now the really fun part, what to choose!  Check at your local nursery to see what they have in stock and/or what they may be ordering in.  Choose large, undamaged bulbs.  It is also likely that your favourite on-line supplier carries spring flowering bulbs.  I would suggest that you do this well before you plan to plant to ensure that you are able to get what you want.

Tulips – We are all familiar with the large colourful, showy tulips.  Their blooms may be cup shaped, fringed, double or ruffled.  This fall, I plan to plant some, new-to me species tulip bulbs.  While species tulips are smaller than the tulips that we are most accustomed to, they are colourful, very hardy and have a more open flower. 

Hyacinth – You can not beat the magnificent fragrance of hyacinth blooms in the spring.  They come in several colours, single or double and are accompanied by strong, strappy leaves.  Hyacinths also produce nectar so provide food for some of our early foraging pollinators.

Narcissus – The spring flowering bulb, in the genus Narcissus, is more commonly called a daffodil.  Bloom colours range from bright yellow to cream to white and combinations of these colours.  Daffodils are cheerful flowers.  I always smile when I see them especially in a natural setting.

Crocus – Crocus “bulbs” are actually corms.  What is the difference??, check here.  These are probably the first of the fall plantings that you will see in the spring. Crocus blooms are tube shaped and come in various colours.  The plant is low growing and does well when naturalized.

The above are some of the more often seen spring flowering bulbs but there are more.  Please see Landscape Ontario  for additional suggestions.

Outcompeting Invasive Plants, Part II

By Laura Gardner, Master Gardener in Training

This article was published in err a couple of weeks ago, and is being republished today as a corrective measure. Apologies. -Ed.

Back in a June post[i], I referenced the Ontario Native Plant Council’s best management practices for Alliaria petiolata (Garlic Mustard).[ii] In it they referred to certain native plants that can be used to outcompete it. I would like to mention one other that I am fond of having in my garden. Packera aurea (Golden Groundsel) has a diminutive orange inflorescence and is native to the Peterborough area. It can be aggressive as it reproduces through rhizomes and adventitious shoots on the stems. It is better situated in moist soils and so it may be more subdued in a drier location. In her blog, The Humane Gardener[iii], Nancy Lawson discovered that when she inserted clumps of Golden Groundsel into patches of Garlic Mustard, the latter quickly became surrounded. Garlic Mustard is known to be allelopathic and inhibits the growth of some plants. However, Golden Groundsel does not appear to be inhibited by it.

Golden groundsel, Packera aurea

Anemonastrum canadense (Canada Anemone) is a beautiful vigorous native ground cover that performs well in sun to shaded environments; although it can develop brown leaves in more arid conditions. I am using it to limit the advance of Campanula rapunculoides (Creeping Bellflower). The intent is to envelope it so that it is unable to photosynthesize, grow more foliage, and store energy in its roots. One might argue that this is simply a matter of replacing one problem with another. While it is true that Canada Anemone can be overwhelming, it may be limited by deadheading the flowers, removing rhizomes, adding mulches, and by installing edging below the soil surface. As a native plant, it supports pollinators such as miner bees, sweat bees, and hover flies. The Xerces Society notes that it supports “conservation biological control.”[iv] This is a plant that attracts beneficial insects to your garden which in turn will help control other insects that damage your other plants.

So far, the Creeping Bellflower’s development has been slowed but there are still some basal leaves within the patch and at the perimeter. Right now, it is still a team effort: Canada Anemone and me.


[i] Outcompeting Invasive Plants: Part I. https://peterboroughmastergardeners.com/2022/06/13/outcompeting-invasive-plants-part-1/

[ii] Garlic Mustard (Alliaria petiolata): Best Management Practices in Ontario. Ontario Invasive Plant Council.  https://www.ontarioinvasiveplants.ca/wp-content/uploads/2016/07/OIPC_BMP_GarlicMustard.pdf

[iii] How to Fight Plants with Plants. The Human Gardener. Online: https://www.humanegardener.com/how-to-fight-plants-with-plants/

[iv] Habitat Planning for Beneficial Insects: Guidelines for Conservation Biological Control. Xerces Society. http://www.xerces.org/publications/guidelines/hab

Outcompeting Invasive Plants, Part II

By Laura Gardner, Master Gardener in Training

This article was published in err a couple of weeks ago, and is being republished today as a corrective measure. Apologies. -Ed.

Back in a June post[i], I referenced the Ontario Native Plant Council’s best management practices for Alliaria petiolata (Garlic Mustard).[ii] In it they referred to certain native plants that can be used to outcompete it. I would like to mention one other that I am fond of having in my garden. Packera aurea (Golden Groundsel) has a diminutive orange inflorescence and is native to the Peterborough area. It can be aggressive as it reproduces through rhizomes and adventitious shoots on the stems. It is better situated in moist soils and so it may be more subdued in a drier location. In her blog, The Humane Gardener[iii], Nancy Lawson discovered that when she inserted clumps of Golden Groundsel into patches of Garlic Mustard, the latter quickly became surrounded. Garlic Mustard is known to be allelopathic and inhibits the growth of some plants. However, Golden Groundsel does not appear to be inhibited by it.

Golden groundsel, Packera aurea

Anemonastrum canadense (Canada Anemone) is a beautiful vigorous native ground cover that performs well in sun to shaded environments; although it can develop brown leaves in more arid conditions. I am using it to limit the advance of Campanula rapunculoides (Creeping Bellflower). The intent is to envelope it so that it is unable to photosynthesize, grow more foliage, and store energy in its roots. One might argue that this is simply a matter of replacing one problem with another. While it is true that Canada Anemone can be overwhelming, it may be limited by deadheading the flowers, removing rhizomes, adding mulches, and by installing edging below the soil surface. As a native plant, it supports pollinators such as miner bees, sweat bees, and hover flies. The Xerces Society notes that it supports “conservation biological control.”[iv] This is a plant that attracts beneficial insects to your garden which in turn will help control other insects that damage your other plants.

So far, the Creeping Bellflower’s development has been slowed but there are still some basal leaves within the patch and at the perimeter. Right now, it is still a team effort: Canada Anemone and me.


[i] Outcompeting Invasive Plants: Part I. https://peterboroughmastergardeners.com/2022/06/13/outcompeting-invasive-plants-part-1/

[ii] Garlic Mustard (Alliaria petiolata): Best Management Practices in Ontario. Ontario Invasive Plant Council.  https://www.ontarioinvasiveplants.ca/wp-content/uploads/2016/07/OIPC_BMP_GarlicMustard.pdf

[iii] How to Fight Plants with Plants. The Human Gardener. Online: https://www.humanegardener.com/how-to-fight-plants-with-plants/

[iv] Habitat Planning for Beneficial Insects: Guidelines for Conservation Biological Control. Xerces Society. http://www.xerces.org/publications/guidelines/habitat-planning-for-beneficial-insects