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Spring is around the corner and all around the city we’re seeing parking strips full of endless potential.
That often drab looking strip of soil between the sidewalk and the road goes by many different names; parking strips, sidewalk strips, hell strips, parkways, but one thing they all have in common is they are often the most underutilized green space on a property, and also happen to be one of the most visible! The first thing somebody sees when pulling up to your house in an urban environment is the parking strip. Here in Portland they most often look like dead grass and weeds for the majority of the growing season and when a tree is planted in the parking strip it is often not appropriate for our Mediterranean climate and struggles to light up the street like it was intended to. But the parking strip doesn’t have to be a no-plants-land of drought and misery! With the right plants and a few tricks and techniques, it can be on one the most vibrant focal points on your property.
Parking strips come in all different shapes, sizes, soil types, solar aspects and size constraints due to vehicles and overhead power lines. The City of Portland has actually come out with a helpful guide for choosing an appropriate tree species given the parameters of your parking strip: https://www.portlandoregon.gov/trees/66682
And while the city’s guide is a great starting point, their tree list is exceptionally limited and often ecologically innapropriate. It should also be noted that if you wish to plant something that is not on the city’s approved list you must ask for a special exception permit to plant your desired species. Also, shrubs, sub-shrubs and perennials are not approved for parking strip plantings and any plantings not approved by the city are considered “private encroachment in the public right of way”. Thankfully unless you’re pulling other permits for new construction or development our lovely city officials will never come bothering you about your parking strip beautification projects, so let the beautifying begin!
There are a number of factors that go into choosing what makes a good parking strip plant. The first and most obvious is that it does not disturb the sidewalk or road due to roots lifting up the pavement. Thankfully most dwarf fruit trees and shrubs don’t pose a threat to sidewalks, especially when properly pruned. Trees also must branch high enough or be pruned properly so cars of all sizes can still park beneath them and plants can’t be growing into the sidewalk to the point that they restrict access for pedestrians and ideally will not grow much taller than any overhead power lines that might be present.
Besides those relatively easy to meet spatial requirements there are a few cultural guidelines to follow. The first and most obvious in the Pacific Northwest is to choose drought tolerant plants. Many parking strips have been backfilled with coarse sandy soil to allow for maximum drainage for all that rainfall that is washing into them from the surrounding impervious sidewalks. But well draining soils are extremely valuable, especially in climates like ours that receive so much rainfall when many of our plants are dormant. Choosing the drought tolerant plants that will thrive in these soils is crucial, but of course most fruiting plants require a good bit of water to set fruit. We’ve created a list of some of our favorite drought tolerant plants here: https://onegreenworld.com/drought-tolerant-plants/
But to really tie the whole planting strip together some groundcovers, perennials and small flowering shrubs are going to be necessary. And here the possibilities are nearly endless! The xeriscape plant palate gives us a ton to work with in these hot dry spaces. Some of our favorites for the parking strips planted amongst and beneath fruiting trees and shrubs include Lavender, Phlomis, Cancer Mt. Bush, Arctostaphylos of all types, Grevilleas, Ceanothus, (especially Centennial, Dark Star, and Midnight Magic), Bottlebrush, Hebes, Agastache, Echium wildpretii, California Zinnia, cold hardy Agaves, Eryngium and Yarrow. Many of these plants are also excellent pollinator and beneficial insect attractors and make great companions to your fruit trees and contribute to a diverse garden ecology.
Water is typically the most limiting factor to a truly flourishing parking strip, and while many of your drought adapted companions may be fine without any water after establishment most fruiting trees and shrubs will need some amount of additional water to maintain good health and vigor and set good crops. But given the fact that there is a sidewalk separating you and your lovely new parking strip garden the task of getting water to your plants can be difficult. But there are some crafty solutions.
The first and most drastic would be to hydro tunnel beneath the slab and run an irrigation line from your property to the parking strip. This is often not possible and is probably not entirely legal, but it sure is nice to have a drip irrigation system running right along your parking strip! The next and likely more practical is to set up a drip irrigation system or soaker hose along the length of your parking strip and simply run a garden hose across the sidewalk and connect to the irrigation line whenever you need to water. Most drip systems need to be on for multiple hours so running your garden hose across the sidewalk in the early morning hours when there isn’t a lot of foot traffic, (and when you should be watering anyhow), makes for an easy solution to bringing that precious life giving water to the parking strip. Other strategies we’ve seen are tree gators or arroyos, which are essentially vessels that slowly drip the water out over a period of many hours in order to achieve a deep watering and keep the water from running off the soil’s surface. Hand watering is also an option, and though labor intensive can be quite meditative if you don’t have to hand water the whole garden and this method is certainly the most conducive to meeting all of your neighbors! And as always a deep mulch helps to build soil and increase moisture retaining organic matter in the soil. Slug problems also appear to be lower in the parking strip and most of our recommended species are not bothered a bit by slugs, so a deep mulch has many benefits and few downsides.
While this subject could fill many a book, we’ll go with a few simple guidelines. First, when in doubt get your soil tested. Heavy metal contamination is the primary concern for many folks and the most common culprit that comes to mind is lead paint from old houses. But many people might be surprised to know that their urban block was at one time used for agriculture not so long ago. In some of these places, such as where we are currently sitting in the Mt. Scott Arleta neighborhood of Southeast Portland there were many old apple orchards. And where there are old apple orchards there is often lead and arsenic leftover from the lead arsenate pesticides that were frequently used before Rachel Carson’s groundbreaking Silent Spring ushered in a huge array of environmental regulations and brought an end to the era of lead arsenate but the heavy metals may still linger in your soil. While many heavy metals accumulate in stems and leaves rather than fruits and it has been argued that it is safe to eat fruit grown in contaminated soils it might not be the most comforting feeling. If you feel your soil is too contaminated for fruit growing then focus on a beautiful xeriscape parking strip.
The most ubiquitous pollutant we come across in urban parking strips is the waste products left by our four legged canine friends. The “burn” spots caused by these leg lifting hounds is caused by an excess of nitrogen and salt build up in the soil that leads to brown spots in lawns or stunted plant growth. Thankfully a thorough soaking by the garden hose can dilute the urine to the point that it might even help your plants out with a little boost of nitrogen, but it is often impossible to tell where a dog has left its mark. Simple signs that request dog owners not let their pups urinate or poop in your beautiful parking strip garden can be effective but dogs often don’t read your signs and pee on your plants anyways. For this reason we recommend not growing any low growing fruiting plants. Strawberries and lingonberries covered in dog pee just don’t taste as good. Also avoid phosphorus sensitive species, such as Grevilleas on the parking strip edge where they might receive the occasional golden shower. We have found that planting densely along the edge of the parking strip often deters dogs from stopping to leave their mark on your garden.
Exhaust fumes and pollutants stirred up by cars passing by can be another concern, but dust and exhaust can easily be cleaned off before eating.
Now the first thing to be aware of when planting and caring for a tree in the public right of way is that many folks will look at it as just that, a public fruit tree. And it should be! But it often feels unfair to have spent all that time and money on caring for and nurturing a young tree only to have the fruit harvested by somebody else. What one of our friends in Seattle has done after a few too many fruit robberies is posted a sign that says, “if you’d like to harvest from this tree, please help me water, prune, and take care of it” followed by his phone number. What a way to meet your neighbors and have a community supported fruit tree! If you’re really lucky you might even get to hear some amazing stories about your neighborhood and some old timers’ lives as they sit on your porch eating your fresh figs and recounting the time they ran through the jungle for 9 days without food in an attempt to escape South Vietnam, stories that only perfect tree ripened fruit can bring about!
On the other side of the harvest spectrum, and a reason why fruit trees in the parking strip get a justifiably bad rap, is fruit going unharvested and falling on cars and sidewalks. An overgrown and unpruned tree dumping tons of diseased fruit on the sidewalk is an image that pops up for many folks when bringing up the idea of planting fruit trees in the parking strip. For this reason we urge you to properly maintain and prune your fruit trees if you are going to plant them in a public space. And if you get to a point where you have more fruit falling from your bountiful parking strip than you have time to harvest, hop on one of the many community forums that exist and urge your neighbors to come take part in the harvest! Make a bunch of jam or dried fruit and give it to friends or the food bank. And if you still have leftover fruit after opening up your tree to the community a nice holiday fruit wine is sure to get your friends and neighbors excited about fruit in the parking strip.
And if not a fruit tree, at least plant something instead of brown grass in that precious green space.
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