(I will add pictures to this page as I take them this summer.)
Our garden is on a narrow urban lot, although it is somewhat deeper than a standard urban lot because of an unusual placement for utility poles. It is shaped like an "L" with the house sitting atop the L and the driveway coming up along side it (to a detached garage that is sitting in the bend of the L). Our yard is fairly sunny, with some shade from nearby trees and buildings. We are in zone 5. We have used no pesticides or herbicides or chemical fertilizers on the yard since we moved in approximately 10 years ago. The yard is divided into three major sections: The patio (at the top of the L right behind the house and next to the driveway), the veggie garden (next to the garage), and the way back, which is the bottom bar of the L.
Here's a video from June 2013 of our garden:
The most traditional part of our garden, the patio is right outside the house and provides a pleasant space for adult relaxation: I am typing at my patio table right now, while my kids dig in the dirt. (Being right next to the house provides an excellent wifi signal.) The patio consists of a brick patio and a small grassy area where we can lay out blankets for babies to crawl upon. At one corner of the patio area is a fairly formal flower bed consisting entirely of plants that provide food for native butterflies and birds -- a crabapple tree, two varieties of milkweed, various lilies, mums, black-eyed Susans, and purple coneflowers. From inside the house or on the patio, we can watch these animals come and go. A small stream runs from our gutter and sump outlet down to the butterfly bed, about 25 feet from the house, where it soaks the swamp milkweeds to make them happy and solves an earlier situation where the sump outlet three feet from itself and immediately repumped whatever it had just pumped out. Along the far side of the stream is an herb bed. (The stream is both pretty and useful, but the children do love to splash in the water and pull all the rocks out of it, which can get a little messy.) Along the house we have a bulb bed that provides a burst of early spring color and my special pet bed, a "black and white" garden that consists of day-blooming black flowers and night-blooming white flowers, so anyone sitting on the patio in the evening can watch the moonflowers open as the black flowers fade into the dusk.
The patio has a round table with an umbrella that accommodates four for dinner easily (six if you are all very good friends and have small plates), and we eat on the patio frequently when the weather is good -- not least because it saves clean-up with two small and messy children. The patio also accommodates two rockers and a double-glider, a couple of small side tables, and a potting bench that doubles as a bar when we throw parties. The side tables and potting bench are essential for eating frequently on the patio, as the patio table isn't really large enough for serving dishes.
The patio's primary purpose is to serve as an area for conversation and relaxation, an extension of the living spaces in our small house, where parents can comfortably watch children and everyone can enjoy the weather and nature.
Maintenance: The bird and bulb beds, being well-established, require a spring and fall clean out and sometimes new mulch; otherwise, they are self-sustaining. The grassy area must be mowed, and the herb bed requires normal maintenance for food plants. The black and white bed requires considerable work but is my special project so I don't mind. Perhaps 5-10 minutes every two weeks to mow, plus half a day of clean-up in the spring and fall.
The Veggie Garden
The veggie garden, which consists of 10 raised beds of various sizes arranged in a square pattern, is exactly what you'd expect. It is separated from the patio by a low (24"), formal-ish hedge that provides visual separation and mostly hides the chicken wire protecting the veggie garden from rabbits. The children help plant and harvest the beds, which are primarily my husband's project. We grow both useful food we will eat -- lettuce, tomatoes, radishes -- and foods that are less-practical but fun to grow, such as unusual hot peppers and corn. Every year we give the children one bed of their own, which is halfway planted with plants they choose, and halfway left empty for their trucks to have special dirt to dig in. (As they get a little older, we will probably designate a bed for each child.) We have the children choose what they want to grow, helping them look through seed catalogs and books on gardening, then letting them choose the plants and seeds at local nurseries. This year, they chose two tomatoes (one full size, one grape), "yellow flowers" (marigolds, they decided on), and radishes. Not many of their plants make it much past a month (except the tomatoes, in colorful tomato cages), but that's all right. They have their own gardening tools (pick up multiples cheap on clearance, they disappear) and gardening gloves.
The veggie garden helps the children understand where food comes from, as well as providing a steady supply of lettuce and a somewhat less reliable supply of tomatoes and other vegetables for our summer eating. My children are not picky eaters, but they do get special joy in eating vegetables they helped grow. It also helps with learning responsibility, patience, and adult work, as they help their father with various tasks.
Maintenance: With around 200 square feet in cultivation, this is a very large vegetable garden and requires considerable maintenance. The raised beds and chickenwire fencing took a considerable one-time investment of time to put together and prepare; the first set lasted 10 years before requiring replacement. A far less time- and space-intensive vegetable garden (a single 4x4 bed, a border bed along a fence, or even a planting box) could easily provide all the benefits of a larger one to child.
The Way Back
As far as children are concerned, the "way back" is the crown jewel of the garden. It is separated from the vegetable garden by an inexpensive decorative fence with a small gate, which makes the way back seem like its own world -- a world largely separate from the intrusion of adults.
The way back is centered around a large "island" of native tallgrass prairie plantings. By the beginning of June, the flowers and grasses are too tall for the children to see over; by July, they're too tall for anyone to see over. As far as they can tell, the loop that runs around the prairie island is endless; the blocked sightlines make the yard seem larger and more of an adventure when the children explore it. We intend to add a winding pathway or two through the prairie itself eventually, perhaps with a secret spot in the middle for the children to hide. The prairie provides a great deal of habitat for native birds and insects (and rabbits) and we can see a great deal of wildlife when we sit out near it (and the boys frequently have the satisfaction of startling and being startled by ground-foraging birds as they run past and the birds take off).
The prairie island is ringed by a grass path about 2 feet wide. (Both the island and the path are irregularly shaped.) Along the outside of the path are a variety of beds. Immediately behind the veggie garden bed is a bed of sunflowers, with "mammoths" that grow at least 12 feet tall in the back and 6-footers in the front, providing more visual separation and a great deal of entertainment with squirrels and birds desperate for the seeds. (Plus, there is nothing as wonderful as 12-foot-tall bright-yellow flowers as big as your head.) Continuing clockwise, we have a compost bin in the corner (another excellent chore for small children is taking scraps from dinner out to the compost bin), then fruit trees espalied along a privacy fence. The next corner has a variety of ornamental flowers and a small table with two chairs (that I call my wine-drinkin' table and the children like to sit at to rest from running in circles). The back fence has grapevines along it, two apple trees starting to form an arch over the back gate, and various ornamental plantings.
Along the nine o'clock side of the way back, behind the garage, there is a little more open space, up to 8 feet. Here we have a small toddler swingset and slide, a hammock, and a playhouse. This area is not very visible and so we don't worry too much about maintaining it (plus all the tiny feet trampling it keep it pretty well down). The kids can play and destroy as they like in this part of the yard, with the playhouse serving as a secret hideout, alchemist's shop, house, castle, or pirate ship as the game requires. Immediately behind the garage, an overgrown elderberry bush (around 10 feet tall) has been cut out on one side to create a "green tunnel" which goes to a variety of imaginary worlds. We even built a doorway for them out of scrap wood, with a low lintel that discourages adult intrusion. It is 5 degrees cooler in the green tunnel than anywhere else (we're thinking it needs a reading bench of some sort for hot afternoons).
The children's area of the yard is studded with weird and wonderful things -- the doorway to the tunnel, a hanging bell, a couple of large gears mostly buried in the dirt, a small brass turtle, a solar-powered LED light, odds and ends for building little structures. A variety of wood offcuts from building the raised beds now serve as "rocks" for playing hot lava along the path and jumping from one to the next, or make a road for toy cars. Structures build out of sticks, rocks, and other miscellanea are left alone until the children are done with them.
Maintenance: The native prairie island requires virtually no maintenance (cutting it down once a year in the spring, basically). However, establishing a native prairie planting (especially such a large one) requires considerable work for the first two or three years as you weed out invasive plants and encourage the prairie community. Once it is established, it takes care of itself quite well, but the establishment of it is very time-intensive. The path requires mowing once every 2-4 weeks (somewhat less than other lawns because of high foot traffic from running children). It shouldn't take very long, but it's a lot of edges and odd sizes, so it ends up taking a little more time that square footage alone would suggest. The children's area requires occasional attention to keep the invasive weeds from taking over and to ensure the tunnel stays tunnel-y, but we most leave it alone and let it be their space entirely. The beds with fruit trees and ornamental flowers obviously require a bit more work at the beginning and the end of the year, but well-mulched they do mostly take care of themselves.
This was not a one-year project. It was tackled in sections, starting with the area near the patio, and begun before we had children. We had a general grand plan that we refined and made specific as we got to each section. You want to get trees in as quickly as you can, since they take the longest to grow to a reasonable size. But if you have a baby now and start this year, you can have a fairly creditable imagination garden by the time your child is two or three, and a robust one with many mature plantings by the time your child is five. If your yard is large, dividing it into sections or "rooms" definitely helps both with planning and with tackling the project one area at a time. You might also consider a landscaper to come in and dig out the large beds (backbreaking by hand!) and plant some of your larger plantings -- a one-time investment that gives you a jump-start. Also consider how you can re-use overgrown parts of the yard; some overgrown abandoned bushes provided our green tunnel with no work on our part except cutting it to be a bit more tunnel-shaped in the tunnel area (for less eye-poking).
In general, planting perennials and natives will require less work from you over time, but they often cost more time and money up front. Once established, they will only require attending to once or twice a year, rather than weekly or bi-weekly lawn-mowings. Our front yard we have left more traditional to suit the look of the neighborhood.
All our mowing is done with a reel mower, which is practical (and pleasant) with such small areas of grass, and in general we don't use power tools or chemicals in the yard. This is less expensive (and better for the environment), but it does require a larger time input. Some of the time we save by not having a lawn to maintain goes into weeding and trimming by hand; on the flip side, without noisy or fumey engines or fast-whirring parts, all this work can be done while supervising the children playing nearby, and they can help with a lot of it. In a larger yard, or for families that do not enjoy gardening, this may not be practical.
In planning and planting this garden, we hoped to create for the children a garden that provided for variety of needs: Relaxation, fellowship with family and friends, an appreciation of nature both scientifically (food plants, night-blooming flowers, local native plants and animals) and aesthetically, and most importantly, imagination. We tried to create secret nooks and crannies, places to explore; in short, spaces to encourage imagination and wonder and the creation of private worlds free from adult interference. We tried to include areas for physical play (running, climbing, digging) as well as imaginative play, places for children to engage the adult world, places to escape together from the adult world, and secret spots where a child can go all alone to read or imagine.
A back yard can be a whole world, especially to a small child, and we tried to encourage this by limiting sightlines, creating a variety of different sorts of spaces that flow into one another and so, and making twisting paths that encourage you to turn the next corner and sometimes lead you into secret, secluded spots. By cultivating our garden, we hope to cultivate wonder.