Rain Gardens

Urbs Pluvialis  The Rainy City

The Problem:

The average urban home is surrounded by impervious surfaces such as roofs, concrete sidewalks, asphalt and even grass lawns.  When the rain falls, it hits these surfaces and most of the water keeps moving, carrying toxins, pollution and an overflow of water toward the storm drains and sewer system.  The sewer system, in turn, becomes backed up and pollutes the local water ways.  The excess surface water also can cause erosion and flooding.  Luckily, there is an easy way to capture the rain and make better use of it.    

Rain Wise

The Solution:

Rain gardens absorb rainwater runoff and storm water overflow.  They create a basin that stores the water and slows percolation, allowing for total absorption into the soil.  The filtration process that occurs when water passes through the soil actually cleans the water and removes pollutants.

How it works: The key is to make a garden that is permeable and absorptive.  This is not your average veggie or perennial garden.  A rain garden must be placed in a specific spot in your yard where it will capture rain water running slightly down hill from your home and at least 10 feet away from any structural foundation.  It is best to use a flat area in partial to full sun that is not near a septic field, or right under a tree.

Rain Wise

How to build one: Before starting out, test the drainage capacity (watch the area in a heavy rainfall or dig a few holes to fill with water and observe the rate of absorption).  The placement of the rain garden can be either directly connected to your gutter (with the help of a length of pipe if necessary) or it can be placed in an area where it will catch runoff from other parts of your yard (e.g. at the bottom of a grassy lawn).   After calling to determine utility lines, dig out your rain garden (initially about 100 square feet and about 8 inches deep for the average home).  In order to maximize permeability, fill the bottom layer of the garden with crushed gravel, followed by compost-enriched soil and topped with mulch or shredded leaves and shredded wood.

What to plant: Natives.  You want your rain garden plants to do well in any season (in the northwest, the plants must be able to absorb heavy and consistent rain all winter followed by several dry months in the summer).  Look for plants with large and deep roots that will be most absorbant.  It's best to use established plants so that the root systems are already strong and ready to work in the rain garden.  The Brooklyn Botanical Garden has a good list of rain garden plants by region.

City Perk:

The city of Seattle is offering a 80-100% rebates for residents who install rain gardens in certain areas.  Watch this clip from King 5 News for more information:

What else you can do:

If a rain garden just won't work in your yard, there are a few other ways you can help prevent water runoff and pollution.

1. Buy a rain barrel or cistern to attach to your downspout.  This will store up filtered rain water for your personal use as needed.  Place small rocks around the barrel or cistern to catch any overflow.
2. Place small rock-filled trenches under downspouts and at the end of driveways to catch runoff.
3. Replace driveways and patios with porous pavers or at least replace of your impervious areas with green material to increase absorption capacity.
4. Install a green roof to absorb rain water before it even hits the ground.
5. Add compost and top dressings to your beds. This will increase the absorption rate of your plants and the compost will actually store many times its weight in water and keep your plants hydrated even when the rain stops.

Rain Garden Resources:

Rain Wise (Seattle Public Utilities)

Healthy Landscapes (University of Rhode Island)

Low Impact Development

Anne Lovejoy's Handbook of Northwest Gardening (Sasquatch 2003)

New Zealand

Summer in New Zealand

There's no better way to break up the winter than going south (way south).  Recently I was fortunate enough to spend a few weeks in the sun, exploring Kiwi urban, rural, and back country life. 

A Brief History:

New Zealand is really a plant lover's dream.  Its flora and native fauna are unique due to its severe isolation from other land masses.  New Zealand was originally part of the super continent Gondwana, covering the southern hemisphere (in plate history, Gondwana followed the breaking up of Pangaea).  New Zealand then split from the super continent before the real Age of Mammals (explaining the lack of native mammals on the islands).  The result of this brings us a country with native flora and fauna (birds especially) that can be found nowhere else.  I can confirm that the trees look ancient and every few hundred feet I saw a plant I had never seen before (one source states that 80% of New Zealand plants are found only in New Zealand*).  I will share a few favorites, some old and familiar to me and some brand new.

 Ferns

 Button Fern

Ferns are a source of Kiwi pride.  There are over 150 native fern species and the Ponga or Silver Tree Fern is a national emblem, decaled on everything from coffee mugs to Friendrich Hundertwasser's famous flag (in new growth frond form) to the All Blacks Rugby team.

http://www.prints.co.nz/

Hundertwasser's Koru flag

Ferns, like most Kiwi plants, are evergreen.  Though ferns are common in many other places in the world, the variety found in New Zealand is remarkable.  The photo below was taken in a fern sanctuary of sorts on the Domain in Auckland.

Ponga (Silver Tree Fern)

New Zealand Flax

  

New Zealand Flax or Phormium is one of the few native New Zealand plants that made it way to the northwestern U.S. This plant is a sun-loving evergreen perennial.  In Seattle, Phormium is generally used as a feature ornamental plant, but in New Zealand, it lines the highways of Auckland and forests of flax help maintain the coast line along the eastern shores of the north island. Thus, the sharp leaves and delicate bright flowers of this plant can be seen all over the country.

Phormium plants are made of a strong material that was traditionally used for basket weaving and in textiles by the Maori people of New Zealand.  Seeds from this plant were first propagated outside of New Zealand after the explorer Captain James Cook's initial visit in the 1770s.

Pohutukawa

The name Pohutukawa is Maori in origin.  The Maori people first populated New Zealand or Aotearoa ("land of the long white cloud") around 800 CE coming primarily from the Polynesian islands.  Many native Kiwi plants have maintained their Maori names.

The Pohutukawa is nicknamed the New Zealand Christmas tree because bright red flowers emerge from the tree's dark green backdrop at the end of December (the beginning of Kiwi summer).  The evergreen tree is mostly found throughout the north island and along the coasts of both the north and south islands.

 Manuka

Manuka or Tea Tree is a small tree treasured for its distinitive honey.  The honey made from its flowers' nector is sold widely in New Zealand and consumers praise its medicinal and antibacterial qualities.  Captain Cook and his crew used to brew Manuka leaves for tea, hence the name Tea Tree.

Kauri

 

Kauri are beautiful trees that, when left to grow, develop a massive and impressive trunk.  Kauri bark was readily used for construction and its resin or gum also had many uses such as chewing, torch fuel and insect repellent.  The Kauri is the longest living tree in New Zealand (some up to 2,000 years old) and it can reach heights over 150 feet.

Totara

The picture above is of a young Totara.  This tree will go on to be about 100 feet tall.  The Maori called the Totara a chiefly tree and used its wood to build giant war canoes (sometimes cut from one log), weapons and for carvings.  It is an evergreen tree and found primarily in New Zealand forests (or "the bush" as the woods are called in N.Z.).

Cabbage Tree

The Cabbage Tree or Ti Kouka in Maori is a New Zealand favorite.  The spiky native tree is humorously compared to the Dr Seuss's creations in The Lorax.  The Cabbage Tree is ubiquitous, seen all over the country.  Traditionally the tree had many uses.  It was cultivated as a food source and in textiles.

Spinifex

Erosion along the Kiwi coastline is an ongoing battle.  Spinifex is commonly planted along the dunes (it's a native grass but its spread is manually encouraged where needed).  The root system allows this grass to stay put despite the transient sand around it. 

Urban New Zealand

After spending time in Auckland, the colonial efforts to bring familiar plants to a new colony are clear.  The British installed plants from all over its empire, greatly diversifying the Kiwi flora.  Here is a look at the lovely Prince Albert Park in downtown Auckland. 

Jacaranda, native to the Caribbean and surrounding area, in bloom

The Moreton Bay Fig tree, named for its place of origin in Australia

Red Canna Lily originating in the Americas.

Go visit

The ancient plant life makes flora exploration feel like a trip to unchartered territory.  New Zealand offers a glimpse of the co-evolution of a plant and bird life that grew to depend on each other and developed their own ecosystem.  As a self proclaimed horticulturalist it was a fantastic trip and the people are great too!

Bring this

I was fortunate enough to receive Andrew Crowe's Which Native Tree* as a gift during my visit and was so pleased with it that I bought his Which Native Forest Plant and Which Native Fern to complete the set.  Crowe's plant and tree identification process is so logical.  He begins with the leaf (using a hand drawings of multiple types of leaves) and then helps your deduce the plant you are searching for by periodically breaking plants down into subcategories (based on size and shape and so on).  They are terrific books and are small enough to tote around on your visit.

Native Plants and Climate Zones

NATIVE PLANTS

The installation of native plants is on the rise in the organic gardening world.  As the name states, here in the US, native plants are those which have originated in North America and which have evolved to excel in a specific region.  They are easier on the environment because they need no extra water than the rain fall that occurs naturally in their region.  Also, they have evolved to a resistance to pests and need little or no fertilizer when planted in the appropriate spot.  They are called "low-maintenance" plants for all of these reasons and lists of your native plants can easily found online (I like http://www.plantnative.org/). 

Beyond strictly native plants, it is possible to incorporate plants from similar climate zones in order to expand your plant list.

CLIMATE ZONES

http://www.usna.usda.gov/Hardzone/ushzmap.html

The climate hardiness zone map is great place to start when you want to make sure a certain plant will make it through your winter since every plant is labled with its appropriate zones.  This map doesn't account for rain or snowfall or for high heat hardiness but these factors can be found online as well (check out http://www.noaa.gov/ and http://www.ahs.org/ for more information).  Once you establish what climate zone you are in, it's time to pick out your plants, which leads us to Project #2: Making Sense of Plant Tags.

Project 1 Curriculum

Garden Education

As they come up, I will try to add some curriculum ideas.  Generally, they will be activities that I have not yet tried in the classroom but they act as a place to start--a collection of ideas that will hopefully be useful in the future because this field is so important in a modern curriculum.  A garden education can teach students how to take in more from their surroundings in order to understand the significance of the food they eat, the trees and plants they walk past, the water they drink, the air they breathe and the trash they throw away.  Here are a two ways to bring Project 1 into the classroom:

1. Native Plant Exploration

Teacher: Bring in 5-7 samples of plants that are native to your area (even better if they are from your school yard or neighborhood)
Students: In groups, look up one of the plant samples in research books or on pre-approved websites and create a poster or presentation and share with the class.
Information given on the poster would vary from one age group to the next but would likely include the plant name, the type of plant (shrub, tree, flower), pictures or drawings of the plant through different seasons and through different stages of life (seeds, new growth, how tall and wide it is meant to get).  Put the posters up for display and come back to the project whenever the season changes!

2. Garden Timeline

It would be ideal if every school had a garden.  The garden could provide food for the students and act as an almost year-round teaching tool (depending on your region).  Unfortunately, most schools do not have gardens but there are ways we can work around this.  As students are learning about vegetables and planting seasons, a calendar or timeline could be created by the students (maybe placed as a boarder around the walls of the classroom) to which items may be affixed.  Either actual seeds or drawings or pictures cut from magazines could be attached to mark the month or season when a specific plant must be sown.  Then, farther down on the timeline, at the common harvest time for your school's region, another picture or drawing can be attached to show which plants are harvested when.  To further emphasize the timeline for each plant, colorful string could link the seed sowing date to the harvest date.  This project creates a sense of the time and effort that growing veggies will take and allows for an ongoing (and colorful) classroom project that can be added to as time permits or as relative units come up.

You could also congruently display your classroom garden on a three by three foot square to gain a better image of a garden space, if space and time permits.  On this square, only the seeds and pictures of plants that are to be sown or harvested that month will be visible, thus the pictures are portraying what the students would see in a garden bed outside.  Keep in mind that in order to cover the entire growing season in one school year, the growing months will have to be condensed!

The timeline and garden square provide a visual record of the seasonal impact on ecology and agriculture.  They show students where their food comes from and how the life cycle of each plant is structured and played out.

Project 1 "Getting to Know the Natives"

Project 1: Neighborhood Walk

Objective: Find out what is in season (what's blooming) and what needs to be cut down (harvested)
This will be split into two categories a) perennials/annuals (i.e. plants to look at) and b)vegetables and herbs (i.e. plants to eat).  So, for the land-challenged, here are some good places to find plants:

a) Perennials and Annuals:                                            
Neighborhood                                            
Public Gardens (botanical and arboretums)    
Public Parks and Campuses                          
Community Gardens                                      

b)Veggies and Herbs:
Farmers' Markets
Grocery Stores (what's cheap right now?)
Neighborhood
Community Gardens

Pick 3-5 of each group (a and b) that strike your fancy then research them.
I will be primarily using The American Horticultural Society Encyclopedia of Plant and Flowers, DK Publishing, New York: 2002; Rodale's Encyclopedia of Organic Gardening, Rodale Press, Pennsylvania: 1978 and Flora's Gardening Cards, Globe Book Publishing Pty Ltd, Australia: 2006.  Identifying plants can be tricky and looking up images online can help but always refer to a legitimate book like an encyclopedia to check your findings.

Keys to Success: Start small.  Each plant has a specific trail of significant names (genus, species, forma, cultivar) and as the plants become more familiar these names will undoubtedly become more important to the urban gardener but for now, the sweet and simple knowledge of a plant's group (genus) will suffice.

Perennials:

Nandina domestica

Nandina is one of the shrubs that fades into the background in summer and then comes alive in the fall.  It is a semi-evergreen and in the fall its leaves are everything from bright green to purple to red.  In the summer there are small white flowers and in the fall you can see small berries beginning to appear on some of the plants I've seen.

 

Sempervivum

Sempervivum (meaning always living in Latin) is a rock plant (as you can see).  It spreads along and is nicknamed "Hen and Chicks" because the smaller rossettes look like baby chicks following around the big hens.  It is an evergreen plant which grows flowers in the summer--you can see what's left of the flower in the picture above.  To remove these you just cut them off at the base. 

Euphorbia

Euphorbias are easier to distinguish from one another when they are blooming.  In this plant you can see the new growth coming through at the base of the plant.  When there is substantial new growth like this you can cut back the larger tops to the new growth but at this late October date, its best to leave it--frost could come at any time and harm a plant which is made more delicate by pruning.  When you do prune this plant, beware of the milky substance that lives in the stem--it will irritate your skin and eyes.

Callicarpa (Beauty Berry)

Beauty Berry is another shrub you could walk by all summer and not notice, then suddenly a small tree filled with shiny purple berries appears and it only gets more vibrant as the winter season sets in.  The leaves (when they're in season) are pale green and there are small light purple flowers in the summer.

The walk around the neighborhood was productive but will work best if it's done a few times a month.  Being able to recognize what plants do well in your neighborhood will help you understand your climate and what plants you may want to use some day when you finally get a small plot in the city!

Next time: The Veggies