The term “invasive species” can mean a non-indigenous species that has a negative impact on its new habitat (like the Asian long-horned beetle). Or it can mean a species, indigenous or non-indigenous, that proliferates in a given area (like the mint plant). Often the two go hand in hand, because when a plant is non-native, it is more likely to take over (like the dandelion, originating in Eurasia). Invasive plant species threaten the biodiversity of native plant life, upsetting the delicate, slowly-attained balance of a natural ecosystem.

According to the Canadian Botanical Conservation Network, the invasive species overtaking our native plants generally have several things in common, making them aggressive competitors:

• Have rapid growth rates in diverse environments
• Produce seeds prolifically
• Are effective at seed dispersal, germination, and colonization
• Often can perform vegetative propagation (a form of asexual reproduction which can be very efficient)
• Are not plagued by pests or natural pathogens
• Can out-compete native plants
• Are too expensive to combat

The following plants are species prevalent in Ontario, with the highest invasiveness risk for the province. Most invasive plant species have their origin in Europe or Eurasia. We know that many of them have been introduced quite recently – in the past century or more.

Originating in Europe

• Garlic mustard (Alliaria petiolata) – competes with the wood poppy (Stylophorum diphyllum), which is endangered, and the white wood aster (Aster divaricatus), which is threatened. Introduced to North America in 1879.
• Dog-strangling vine, Black swallowwort (Cynanchum nigrum). A tough, twining vine that grows in waste places, in abandoned pastures and along fencerows.
• Leafy spurge, Wolf’s milk, Faitour’s grass (Euphorbia esula). Grows on fields, pastures and roadsides. This weed is poisonous to livestock. It propagates vegetatively.
• European frog-bit (Hydrocharis morsus-ranae). Grows in the wet, in areas such as ponds, ditches and canals. Introduced in 1932, the European frog-bit displaces native flora. Propagates vegetatively.
• European buckthorn, Common buckthorn (Rhamnus cathartica). This variety of buckthorn easily outcompetes native seedlings.
• Glossy buckthorn, black buckthorn (Rhamnus frangula). This buckthorn also displaces native species. Both buckthorn species were introduced to North America before 1913.

Originating in Eurasia

• Purple loosestrife, Swamp loosestrife (Lythrum salicaria). The loosestrife has clusters of vivid purple flowers on terminal spikes. It spreads in gardens, ditches and wetlands.
• Eurasian water milfoil, Spiked water milfoil (Myriophyllum spicatum). Thrives in stagnant or running water. Since its introduction in 1960, the milfoil displaces all other species with which it comes in contact. It propagates vegetatively.

Originating in Asia

• Japanese knotweed, Mexican bamboo (Polygonum cuspidatum). Japanese knotweed is sometimes called “Mexican bamboo” or “false bamboo” because of its hollow stems and horizontal joints (nodes). It can have ornamental usage.

The urban chicken

It’s true, Torontonians  are catching onto this trend, following other Ontarian and Canadian cities in taking care of chickens in their very own backyards and bringing new meaning to the terms “urban farm”.  Imagine having the freshest, organic eggs straight from your own flock for breakfast… Toronto Chickens is hosting a film screening of Mad City Chickens to bring awareness to raising chickens in Toronto.

Tuesday August 11th at 7:30pm in UofT’s Sammy’s Student Exchange Cafe in Hart House, come and explore the world of Urban Chicken farming, have your questions answered, and maybe you’ll even catch a peek of our fine feathered friends.  Admission by donation.  Check out the poster for more info: mcc-hart-house

With its large, drooping, dark green leaves and fruit reminiscent of the tropics, the Pawpaw doesn’t seem to belong in Southern Ontario. In fact, the Asimina is the only member of the Annonaceae family found outside of the tropics. But we’re pretty lucky to have it.

Native to most of the Eastern United States and the southern tip of Ontario, Asimina triloba grows in temperate woodlands – either in well-drained, rich bottomland or on hilly upland. Common pawpaws can be grown as container specimens, but it is necessary to have a deep container to allow room for the roots. Its dark red flowers appear in early spring, before the leaves grow. These trees can grow to 11m.

Pawpaws’ leaves, twigs and bark contain Annonaceous acetogenins – a natural pesticide that gives these trees immunity from almost all pests. Also, the acetogenins can be used to manufacture organic pesticide.

The pawpaw fruits in September to October. The fruit is a 5-15 cm long, greenish-yellow berry. It looks something like a papaya, which is probably where its name originates. In fact, the fruit tastes somewhat like both banana and mango. It has large seeds embedded in the flesh. Unfortunately, the cultivation of the pawpaw is limited by difficulty in transport – it must be frozen in order to be preserved. However, it is a perfect choice for local produce where available.

Beneficial Chemical Properties:

The pawpaw fruit is a healthful source of good fats, protein (containing more than most fruits), and complex carbohydrates. The tree also has some of the strongest forms of acetogenins of any tree or plant. These long-chained fatty acids fight insects, parasites, lice, and cancer cells. Thus, as well as providing useful pesticide, the pawpaw has great medicinal value as well. It is hailed by some as an alternative cancer treatment, and pawpaw twig extract pills are now available.

Acetogenins from the pawpaw, as well as from less potent sources in the Annonaceae family (graviola, guanabana and soursop), are the only remedy that has proven effective in inhibiting the growth of multiple drug resistant cells. These cells, which constitute about 2% of tumour mass, cannot be destroyed by chemotherapy and will regenerate into a chemotherapy-resistant tumour. Another benefit of pawpaws as compared with most other alternative cancer treatments is that the therapeutic agents in the pawpaw can cross the blood/brain barrier (a bodily protective mechanism) and treat the brain.

Rather exotic but native, delicious, pest-free and medicinal – the pawpaw has it all. These low-maintenance trees would make a great addition to any backyard or neighbourhood garden.

Nitrogen is pretty important. That’s why we need fertilizers, right?

Fertilizer supplies nitrogen in forms that plants can use immediately or with a simple chemical conversion. This rapid delivery of nutrients is useful as compared with manure and compost, which require longer-term decomposition: most of the nitrogen will not be available to the plants for years.

The use of nitrogen-rich inorganic fertilizers is common, and is becoming even heavier as the demand for food grows. The International Fertilizer Industry Association predicts that we will use 100 million tons in the year of 2010-2011. But too much nitrogen can diminish the quality of crops. Excess nitrogen from fertilizer – usually more than half of the nitrogen – pollutes lakes and rivers (eutrophication) with rainwater runoff. Once they have found their way to the oceans, these high concentrations of nutrients create “dead zones,” killing algae and suffocating fish. Nitrate in groundwater holds the risk of methemoglobinemia (“blue baby syndrome”), a condition in which the blood cannot carry oxygen properly. Nitrogen fertilizer is also a huge contributor to greenhouse gas emissions, and uses natural gas intensively.

Yikes! How else can plants get nitrogen instead?

Gaseous nitrogen – the N₂ found in the air – is unavailable for use by organisms because of its stability as a molecule. In order for this nutrient to benefit crops, it must be “fixed:” combined with hydrogen or oxygen to create compounds such as ammonium (NH₄), nitrate (NO₃) or nitrogen dioxide (NO₂).

Not surprisingly, there are natural processes which can give plants what they need and are superior to synthetic fertilizers, avoiding all of the abovementioned negative repercussions. Some types of bacteria fix nitrogen and reduce the need for artificial fertilizer. The bacteria live in root nodules of certain plants, achieving a symbiotic relationship with their host: the plants provide a site for growth and carbohydrates for nourishment; the bacteria provide nutrients like nitrogen.

Which plants fix nitrogen?

Normally, this nitrogen fixation is performed by members of the legume family (Fabaceae), like beans, peas clover, alfalfa and lupin. The decaying of plants also contributes to soil fertilization.

Another type of plant that has the capacity to fix nitrogen is angiosperms (like alder, ceanothus and Russian olive) nodulated with actinomycete fungi (the Frankia genus). As the trees discard leaves, this decomposing matter enriches the soil with nitrogen.

Forest gardening is landscaping technique modeled after a natural woodland ecosystem. Forest gardens utilize interplanting and companion planting (link) to promote polyculture instead of monoculture. While imitating the functioning of a native forest ecosystem, forest gardeners substitute inedible trees and plants with those which yield food for humans. It is important to include shade-tolerant plants (link), due to the inherent limited sunlight of a forest garden.

The temperate forest gardening concept was applied originally in humid regions such as Indonesia, India, Nepal, and Tanzania, in home gardens. These gardens are characterized by multi-purpose use of land for cultivating trees, crops and livestock. They may be in rural, peri-urban, or urban settings. Interplanting allows for intensive, efficient use of small plots of land. This technique contributes to food security in times of scarcity, but also to everyday cultivation of food for subsistence. This connection with the land and control of food supply empowers communities.

The forest gardening system was developed for temperate regions by Robert Hart in Shropshire, England. He designated seven layers of plants:

1. Canopy (Large fruit & nut trees)

2. Low tree layer (Dwarf fruit trees)

3. Shrub layer (Currants & berries)

4. Herbaceous (Comfreys, beets, herbs)

5. Rhizosphere (Root vegetables)

6. Soil surface (Soil cover, e.g. strawberry)

7. Vertical layer (Climbers, vines)

By following the principles of forest gardening, we can all make the best use of limited urban space. The forest gardening model enhances biodiversity and environmental stability at the same time as it creates a productive, edible garden.

http://en.wikipedia.org/wiki/Forest_gardening

http://edibleforestgardens.com/about_gardening

Edible Forest Gardens Vol. I by Dave Jacke, with Eric Toensmeier

Forest gardening’s “Top 100” species

]]> http://urbanagriculture.seedstoronto.com/2009/08/04/forest-gardening/feed/ http://urbanagriculture.seedstoronto.com/2009/08/04/interplanting/ http://urbanagriculture.seedstoronto.com/2009/08/04/interplanting/#comments Tue, 04 Aug 2009 19:48:57 +0000 Vanessa http://urbanagriculture.seedstoronto.com/?p=141

Interplanting is the practice of interspersing more than one crop in a given area. It is an organic gardening tool that can be used to improve the growing conditions of one or more of the crops. At its best, this companion planting offers mutual benefits to all plants involved. For example, a traditional intercropping combination in Mesoamerica is corn (the main crop) with beans and squash. The beans can climb up the tall corn stalks; the squash provide ground cover, which hinders weed growth. This way, farmers boost their corn yields and increase the efficiency of their fields.

Mixed intercropping is the type employed at Green Oasis: plants are in no distinct row arrangement, as opposed to being planted in alternating rows, bordering strips, or neighbouring fields. Using relay intercropping, we make sure that there’s always something to harvest in the garden by planting new crops with more mature ones. When intercropping, it is important to consider the nutrient and moisture requirements of each plant.

Why Interplant?

It’s a greener way to garden. Companion planting is a natural alternative to pesticides. It also augments biodiversity, as compared with crop monoculture.

It’s a space-saving tool. Especially in an urban environment, space is of the essence. We can be more efficient with our limited resources by using every inch of soil wisely.

It can improve soil quality. Spent plants can mulch newer ones, and certain crops provide essential nutrients: legumes, for instance, add nitrogen to the soil for subsequent crops.

It provides plant markers. Faster-growing crops can mark the location of slower-maturing ones, thus protecting them from accidental disturbance (a frequent challenge in a community garden!). For example, radishes and carrots are often seeded together. The radishes, once they have germinated, signal the position of the carrots.

How Interplanting Works

1. Attracts pollinators. Especially when vegetables lack showy flowers, it can be beneficial to plant flowers nearby with bright blue, yellow, or white blossoms and concentrated nectar. A few good choices: cosmos, larkspur, mints, sunflowers, sweet peas and zinnias. Here is a chart of companion plants to improve crop yields: http://www.gardensablaze.com/Companions/CompanionYield.htm
2. Attracts beneficial insects. Insects that eat common garden pests are always welcome. But it’s necessary to provide certain conditions to keep the insects that we want happy! Parsley, dill, and coriander all help to attract these beneficial insects. Small wasps, which eat aphids, caterpillars and grubs, require plants with tiny flowers like fennel, dill, Queen Anne’s lace, or clover. Ground beetles, which eat ground-dwelling pests, need ground cover in the form of herbs like thyme, rosemary or mint. And hover flies and robber flies, which eat leafhoppers, caterpillars, and others, are attracted to composite flowers like daisy and chamomile, and mints like spearmint, peppermint or catnip.
3. Deters undesired insects. The odours of many plants and herbs repel harmful insects. Some plants hinder the growth of others, though; so for the healthiest plants possible, it’s necessary to be aware of crop compatibility as well as pest control. Here is a chart of plants to deter specific pests: http://www.gardensablaze.com/Companions/CompanionPest.htm
4. Draws pests away from main crop. Trap cropping steers pests away from certain crops by offering “sacrificial” lesser crops that the insects prefer. Collard greens, for example, are often used to protect cabbages from diamondback moths or cabbageworms.

Gardening in the sun is taxing, and most of us are grateful for a little tree cover on a sweltering summer day. However, it can take a little ingenuity to find plants that thrive in the shade – as we gardeners certainly do. Are you in the dark about how to make those sunless areas work for you? Here is your guide to navigating the deepest, murkiest recesses of your garden.

There are three main categories of shade, which will help you determine the varieties of plants that you can grow: light shade, half shade and deep shade. Light shade (dappled shade) is characterized by trees with an open crown, and plants still receive a few hours of direct light. With these conditions, you have lots of options for planting. Half shade means that there is little direct sunlight, but a lot of reflected light. Plants in deep shade (full shade) don’t even receive much reflected light: they may be positioned next to a north-facing wall and under a tree canopy, or under a tree with a dense crown and low branches. It is more difficult to find plants that thrive in these conditions. Find out what kind of shade you have, and consult the growing instructions for the perennials you wish to plant.

Here are a few suggestions for shade plants. Don’t be deterred by the unattractive names of some of these species (barrenwort? Hmmm…).

• Ferns: an ancient plant. Ostrich ferns produce edible fiddleheads; the Japanese painted fern is a popular decorative variety. Growing tips: Different types of ferns have different growing requirements – their native habitats vary hugely. Find a variety that will work in the conditions in your garden. Also, ferns’ surface roots are delicate – do not step or rake near them. You may need to add one to two inches of mulch every year if the crowns of the ferns are exposed.
• Hosta: a must in any shade garden. There are thousands of varieties of this hardy plant, and it creates a beautiful effect to combine gold-, blue- and green-leaved varieties. Growing tips: rich compost is especially important for lush hostas. They may bleach in the sun. A potential problem with hostas is slugs.
• Brunnera: a low-maintenance perennial, with heart-shaped leaves and sprays of blue or white flowers. Growing tips: brunneras need shade to part-shade and woodland soil, as opposed to moister clay soils.
• Lungwort: a member of borage family, with white-spotted foliage and bell-shaped flowers maturing from pink to blue. Growing tip: lungwort requires rich, moist soil for optimal results.
• Barrenwort: Introduced to Europe from China in the early 1800’s, where it grew in shady valleys and on mountains’ northern exposure. Growing tip: Barrenwort grows best under deciduous trees.
• Perennial geraniums (cranesbills): not to be confused with Pelargoniums (which are commonly known as geraniums), true geraniums are hardier than their cousins. Growing tips: half-day sun suits geraniums well. They thrive in rich, well drained soil. Try not to let the soil get dry between watering.

If you’re trying to lessen the shade in your garden (you can have too much of a good thing), prune lower branches of dense trees. The shade of evergreens is especially dense, and it can be difficult to grow many plants under a conifer canopy. Use mulch and try to plant at the edge of the canopy.

Make sure to water your shade garden well! In order to achieve the blooming that you desire, your shade perennials can’t be hydration challenged. The trees providing your shade are also competing for moisture with your other plants: weekly, give your shade garden approximately an inch and a half of water for the trees and an inch and a half for the perennials.

Mulch heavily – 2-3 inches of mulch works well for most plants – to keep in the moisture. Also, maintain the mulch layer to continuously provide your plants with the nutrients that they need in the shade.

Although it rarely seems necessary this summer to beat the heat, shade gardens offer a certain serenity and seclusion. The dark niches in your garden will never have been so zen.

TONIGHT Wednesday July 29th from 5:30pm-’til Dusk, Green Oasis on Broadview is proud to be hosting Gerrie the Worm Lady at the Green Oasis garden for our interactive vermicomposting workshop!

**OUR RAIN LOCATION IS THE ALANO CLUB AT 740 BROADVIEW AVE, 1ST FLOOR**

Come and learn about vermicomposting, have your all your pressing compost questions answered, and walk away with the knowledge and worms to be able to start your very own vermicompost system right in your home or garden.

Gerrie the Worm Lady is doing a roadtrip specially to Toronto to help out with our City garbage problems, and is selling her red wiggler worms for only $25/half pound and $45/pound! Don’t miss this incredible opportunity to be able to get these precious compost-creators and to learn from this incredible woman. And please pass this email on to everyone that could benefit from learning about how to turn garbage into garden soil during this stinky strike time!

What Should I Bring to the Workshop?

The workshop will consist of learning from Gerrie about the vermicompost system, getting everyone set up with their vermicompost, followed by a big salad dinner, courtesy of the Green Oasis garden. There will also be the opportunity to donate to the Green Oasis Garden at the end of the session as well.

The following things should come with you to the vermicomposting workshop Wednesday:
- Sturdy Container (can be made of reused materials such as wood, plastic, or metal to host your wormies in)
- Cloth Cover large enough to cover the top of your sturdy container
- Shredded newsprint (enough to fill your container… and I’m sure you’ve got tons overflowing your recycle bin)
- Tupperware (to harvest greens from the garden and/or to partake in salad eating)
- Fork (to eat salad with)

- $25 for half pound of red wigglers, $45 for full pound

Gerrie the Worm Lady is doing her 4 day Toronto Roadtrip tour from July 27 – 30. New World Perspectives Blog has dates, times & location details. Sign up Today for your Worm Lady Road Trip Newsletter

On a semi-related note, if you just happen to be reading this, and you’re an internet god, please get in touch with us (presumably by email).

For more information on seed bombs, check out:

*this wiki article

*this page by “heavy petal” (cute!)

*this video demo by Richard Reynolds

…or just come by on Wednesday and see for yourself!