Fall is tree planting season. Here’s what you should know about planting a new one, or removing a dead one.

Published on: October 18, 2022 6:00 AM EDT|Updated on: October 18, 2022 4:36 PM EDT

Baltimore Tree Trust staff wheel two 1.5 caliper saplings for a planting at Medstar Good Samaritan Hospital.

Autumn is tree planting season. The soil is warm, the air is cool, and, with luck, there will be rain. As counterintuitive as it might seem, from now until December is the least stressful time of year for the roots of most saplings to become established.

If you are ready to plant a tree now, by all means check for tree and mulch giveaways by the Department of Public Works. The University of Maryland has this tip sheet for those heading out to sales at commercial nurseries and garden centers.

If, however, your goal is to plant a sapling in a city tree pit, now is the time to hurry up and wait. Getting dead trees out of Baltimore’s existing tree pits, and living ones into them, is far more time-consuming. It is a backlog, yes, but one that also amounts to a useful planning window.

Consider this a rough guide to becoming shovel-ready for the next few weeks, or next year.

Where to plant

Don’t be shy about planting away from fence lines in the middle of a garden, where a tree will have a chance to mature without a neighbor hacking off half its canopy. Avoid boggy spots, stay away from overhead utility wires and, as with street trees, if there is any possibility you will be digging near a buried service line, put in an excavation check with Maryland’s Miss Utility.

A Princeton Elm is hauled off a Baltimore Tree Trust truck for planting after a storm in Federal Hill Park.

When planning for street trees, residents with unpaved medians or grassy easements between their sidewalk and curb need to do little more than check neighborhood covenants and Miss Utility, and then file a tree request with the Department of Recreation and Parks’ Forestry Division. Keep the service requests (and their reference number) to share with your district council member should delays become excessive.

If there is not an existing tree pit but there’s potential for one, the first step is to size up your sidewalk. City specifications call for a minimum space of 36 square feet, or variations of 4 feet by 8 feet. Those that have broad sidewalks with a 3-foot clearance for Americans with Disabilities Act compliance might be in luck. The Baltimore Tree Trust and Blue Water Baltimore are expanding tree planting programs to include tree pit creation and expansion.

Across much of the city, however, 6-foot-wide sidewalks festooned with street signs, utility poles, fire hydrants, street lights, meters and garbage make it impossible to meet new pit requirements. The most likely site for a new tree is an existing tree pit. If it can be enlarged, it’s worth doing, says Baltimore Tree Trust CEO Bryant Smith. If it can’t, it can still be replanted. If a pit looks empty, Smith warns to check for a buried stump by driving a spade or pick into the center of the pit. A new tree will need the root to be dug out to a depth of 2 feet. Often with existing tree wells, you won’t need to test with a shovel. The problem will be obvious: dead trees left until they fall over us, and stumps left until we fall over them.

Dead tree and stump removal

In 2018, the backlog for removing dead stumps was so egregious that Council member Isaac “Yitzy” Schleifer dragged a stump section into City Hall, stood on it, and announced that the city was paying more in insurance claims involving accidents caused by stumps than it would have spent removing the hazard. According to Schleifer, a deal struck with former mayor Catherine Pugh reduced a backlog of 3,000 stumps to 1,000. “Then she went to jail,” he said. When Daniel Coy, the city’s new chief forester, took up his job earlier this year, the stump inventory was about 1,500. Schleifer said he is holding fire until Coy has been given a decent interval to learn the ropes. And Coy says the city is trying to jump-start a removal contract with a new contractor while he is bringing a new staff up to speed, including a new coordinator of TreeBaltimore, the city’s replenishment and recycling arm, and a new technician to take over a computerized tree mapping system.

Which tree species?

The choices have evolved since the any-tree-as-long-as-it’s-a-Bradford-pear approach to street trees of the 1970s and ‘80s — but not for you or me. Species selection will still probably be made by a city employee, or nonprofit arborist. Professionals weigh considerations including a tree’s salt tolerance, disease resistance, growth habit, invasiveness, carbon sequestration capabilities and smog resistance. That said, Forestry’s outreach side — TreeBaltimore — will offer choices to groups such as SoBoGreen, whose volunteers include a landscape architect. This is led by Joanna Pi-Sunyer, a sustainability analyst at Baltimore City Public Schools and veteran of almost 20 years of street tree planting. “It’s always a little bit of a dance,” she said, “because we have to put in the request for trees before we know which pits are actually open.”

A columnar ginko on St. Paul Street.

No city is better situated to educate residents who are planting their properties or who would like to collaborate with city foresters on street tree selection. A pageant of our finest regional trees is now on display in full fall glory at the U.S. National Arboretum in Washington and at the Cylburn here in Baltimore, replete with species identification tags. Common species currently being planted around Baltimore — all on Forestry’s approved Street Tree Species List — include serviceberries, London planes, hackberries, Princeton elms, Eastern redbuds and Kousa dogwoods. If you’re looking for a tree for an extremely narrow street, arborist Chad Vrany says to look out for the descriptor “columnar.” Cylburn’s “Newton’s Sentry” maple is so narrow that it could be mistaken at a distance for an Italian cypress.

Which sapling size?

City and nonprofit foresters use 1.5-inch caliper trees for replanting street pits. This measurement, which refers to trunk circumference, sounds small. It isn’t — 1.5 caliper saplings arrive from the nursery standing from 8 to 10 feet tall, weighing 100 pounds or more and with root balls of more than a foot across, and roughly as deep. They are far too big to be safely handled by one person (for the person’s sake and the tree’s). If the opportunity presents itself to start with smaller saplings — ones with roots that will probably come in a plastic pot, instead of the larger sapling’s balled and burlapped cage — take it.

What is gained in size by working with larger saplings (they can’t be easily stolen) is easily lost in transplant damage. Blue Water Baltimore publishes a useful protocol for handling the large saplings, while the University of Minnesota horticulturist Jeff Gillman provides an excellent overview of how to deal with circularized root issues common to smaller trees in pots in Fine Gardening.

Shovels and rakes laid out for volunteers by the Baltimore Tree Trust.

Tools

Blue Water Baltimore gives a good rundown of tools needed, which will include gloves, a pickaxe, shovel and bypass pruners. Pi-Sunyer organizes tools for her volunteers from the ToolBank on the Carroll Park-Pigtown borders. A similar resource is the Tool Library in Station North. Most planting nonprofits will supply tools.

Soil amendments

Modern practice discourages addition of compost to whatever soil is excavated and then filled in around the edges of the planting hole. The logic is that it’s better to accustom the tree to the new ground. However, in clay like Baltimore’s, addition of a small amount of compost can improve permeability and absorption of water for the all-important establishment phase. The University of Maryland warns against planting trees too deeply. The most important addition will be a top dressing of mulch, taking care not to bury the stem. Mulch is available free for community projects, and at notional prices for single residents from Camp Small, the city’s wood recycling center.

Staking and borders

Never leave a nursery stake tied hard against a tree trunk when planting.

Professional crews will drive new stakes set outside the root ball then string ties looped around the tree’s upper trunk to hold the plant upright as its roots become established. Stakes and ties should be removed before the tree grows into the tie, which will girdle the trunk. Ground-level borders to prevent soil compaction should not obstruct drainage of rainwater into the planting well. Blue Water Baltimore has a good photo essay on effective versus destructive borders. Plea to dog owners: Try to steer Fido and Fifi to street signs and hydrants, and away from saplings.

Watering and weeding

The city’s tree request form includes an agreement for care requiring that participating residents will “regularly water the tree, saturating the roots with 20 gallons of water once to twice a week (equivalent to a slow faucet flow for 10 minutes) from May through October, for a minimum period of two years.” This is one reason that organizers such as Pi-Sunyer only plant trees where a nearby neighbor has agreed to take care of it.

The most common device used to help water saplings is the Treegator, or gator bag. It’s a green plastic bag that is strapped to a tree trunk or stake. Filled from the top, the bags slowly release drip irrigation to the soil. Pi-Sunyer removes these from established trees, cleans them, then recycles them for new plantings.

Blue Water Baltimore recommends a plastic ring called a Greenwell, which is installed during planting to concentrate hose water and rain in the root zone. I had success with street trees planted out of hose range with a doughnut-shaped pad called a TreeDiaper. With a good soaking, it lies flat on the soil and its water-absorbing pellets drink up rain when it falls, and release the water when it’s dry.

None of these contraptions are perfect. Gator bags are too rarely removed over winter and, left untended, can create fungal disease at the trunk of the tree. Greenwells can cause swimming pools of liquids other than water. TreeDiapers are expensive and, while they can last two years in good conditions, in rainless ones they dry up and either need to be rewetted with hauled water or they blow away. Regardless of which you use, the single most important factor to getting newly-planted trees off to a good start is timing. While professional crews and many community groups also plant in spring, it’s a multiplier of risks. The best time to plant a tree in Baltimore is the fall, when a tree’s roots begin to establish before the canopy is struggling to stay hydrated against rising heat of spring and summer.

Maintenance

Gradual pruning of a tree will be needed to allow pedestrian clearance, protect trees from traffic and improve branch structure. TreeKeepers is a city program aimed at training volunteers to assist with this, along with weeding and watering.

Partnerships

Blue Water Baltimore and the Tree Trust plant in partnership with local community groups. The Trust will work on replantings for as few as 10 empty tree wells in a neighborhood. Ideally, community organizers can follow Pi-Sunyer’s model of forging a steady-as-you-go relationship over many years with the Forestry Division’s TreeBaltimore.

Street sweeping and leaf recycling

The English synonym for autumn is derived from what tree leaves do — they fall. That brings us to why fall is not only the best season to plant trees, but the main reason why many of us do not do it. One city department, Recreation and Parks, plants trees while another, Public Works, deals with the leaves. Until the Department of Public Works deems street sweeping something that it is actually supposed to do (instead of merely claiming to do it on planning calendars), then many who would benefit from trees in Baltimore will not only decline to have one, they will chase off planting crews. Forty miles down the road, Washington, D.C., recycles its leaves. Council member Schleifer has thoughts about why it’s a scandal that Baltimore doesn’t do it, too — and a ready supply of stumps to stand on when he shares those thoughts in City Hall.

An earlier version of this article stated that the backlog for stump removal had decreased to five to seven months. City officials say they do not offer a time frame for the work.

Emily Green worked with her local block club, the Department of Recreation and Parks’ Forestry Division, and the Baltimore Tree Trust on park and street tree replacement in Federal Hill. Her writing on urban gardening may be found at www.chanceofrain.com.