Don't treat your garden like one homogenous zone---break it down into micro-climates, including different exposures and soil types.
Learn to be realistic about your location. Vancouver used to be a rain forest.
Plant different vegetables from your neighbour—be unique! Plant more than one variety of a veggie, make a rainbow garden, full of a variety of colours. Learn about plant families and be aware of crop rotation.
Get to know your neighbour and gain from their wisdom, swap garden experience and stories because you live in the same micro-climate.
Protect biodiversity and food security by learning how to save heritage seeds to help preserve the world's gene pool.
Succession planting: Think about plants that provide food and shelter for birds and insects all year round and help create pollinator corridors in the city. Avoid hybrids and pollen free varieties, which fail provide insects with their nutritional needs.
Think about your garden in the different seasons—keep a diary of your garden so that you can make notes about “dry periods”, times without blooms, fruit or seed pods. Think about how much garden maintenance is realistic for your schedule and when you will be away or taking holidays. Plant things that will be very low maintenance when you are gone (xeriscaping).
Learn about winter gardening for food plants, but be sure to amend the soil and give it a rest if possible. If you are out all day, think about planting a night garden for moths.
Think about a variety of seeds, textures, blooming times, and foliage, (ie deciduous and evergreen). Think about various heights of plantings and different scales of plant morphology—ie big blooms, medium sized blooms and tiny blooms to attract a variety of pollinators.
Evaluate the eco-function of each plant in your garden. Is it pretty but lacking function? Think about plants that really add eco-value to your garden, ie food, and shelter for wildlife and for you. Use goldenrod as an example.
Include pollen and nectar rich native plants in your garden to support local birds and insects.
Leave some parts of your garden untouched. That's where ground-dwelling bees and wasps might live. Keep a wood pile for insect habitat. Leave your dead stalks up over the winter for insect homes and winter interest. If it drives you crazy, make it pretty by putting it into bundles, but leave it in the garden until well into spring.
Dig up your lawn or perform an intervention on your lawn—find flowers you can naturalize into your lawn, and cut and water it less often.
Think about your arable land as real estate. Increase productivity and blossom density by planting vines and plants that can grow up rather than spreading out. Kiwi fruits, runner beans, etc. Plant flowers that can climb over bushes and bloom. Consider living roofs on sheds, playhouses, and garages. Use less concrete, paving, and decking, and if you do build a deck, use container plants, climbing plants and hanging baskets to provide flower power and shade. Investigate wooly pocket gardens. (http://www.woollypocket.com/)
Create a garden that stimulates your senses: colour and light, scent, texture, sounds and taste, ie lemon balm, lemon verbena, lemon thyme.
Make your garden plan personal and eclectic. Grow the medicine you need. Find your own medicines. Gardens are nurturing habitat for humans. How can you plant a garden that nurtures and cares for you and your family?
Go to Van Dusen Gardens, and local community gardens for inspiration.
Plant in groups of 3's or fives to have some stability and aesthetics within the diversity. Insects do like groupings of plants. Bees and butterflies like groupings of plants at least 3 by 3 feet (1x1 meter). Learn about which plants thrive as communities and which plants are companion plants.
Critters in your garden need food, water, shelter at all stages in their lives. Creating water sources for insects and birds will be a huge step towards encouraging biodiversity in your garden. Just don't leave water standing for mosquito larvae to develop! Water with rainwater when possible and practise water conservation.
Don't use pesticides—stay away from bt (Bacillus thuringiensis)--because it kills butterfly caterpillars. Learn about integrated pest management, or IPM and which plants repel pests.
Be an ivy buster. Learn to identify and banish invasive plants including Gorse, Japanese Knotweed, Leafy Spurge and Purple Loosestrife which are four of the top 100 invasive plants in the world.
Be an Edwardian lady—observe, sketch photograph, blog, write about your garden. The more attentive you are, the more biodiversity you will actually see in your garden.
Use substitutes for peat and sphagnum moss. Mulch with leaves and grass instead of wood chips.
Avoid using garden furniture made from tropical hardwoods unless there is evidence they were from a sustainably managed source.
Buy organic food and cotton. Use eco-friendly cleaners.
Support local seed savers.
Seeds of Diversity—http://www.seeds.ca/en.php
Resources:
Natural Gardening: A Nature Company Guide, J. Knopf, S. Wasowski et al
Insects and Gardens, Eric Grissell
Landscaping for Wildlife in the Pacific Northwest by Russell Link
The Natural Gardener: The Way We All Want to Garden by Val Bourne
My website: http://beespeakersaijiki.blogspot.com/
Invasive plants Council of BC: http://www.invasiveplantcouncilbc.ca/
Natural England http://www.naturalengland.org.uk/ourwork/conservation/biodiversity/threats/default.aspx
Hinterland Who's Who: http://www.hww.ca/hww2.asp?id=222
Wild About Gardening: http://www.wildaboutgardening.org/
Xerces Plant Lists for Pollinators: http://www.xerces.org/plant-lists/
Berkeley Bee Gardens: http://nature.berkeley.edu/urbanbeegardens/