Dear PoPville – How Do These Work?

Dear PoPville,

Can you help me understand these canopy keepers?

They claim to capture and slowly release rain water to aid young tree growth. But, in practice they seem to capture rain water and foster mosquito growth.

38 Comment

  • If the holes are not clogged, 99% of the water will drain out of them. The idea behind them is 2 fold:
    1) It provides a slow (maybe 5 gallons over 10 minutes) stream of water to young trees. This allows the water to infiltrate rather than running off if you spray it with a hose.
    2) It allows someone to adopt a tree that might not be right in front of their house (e.g. you could schlep water 3 doors down where your hose might not reach).

  • Maybe they should come with usage signs. Everyone in my hood thinks they are trash cans.

    • After a few weeks their contents (beer cans, fifths of vodka, skittles bags, cigarettes, condoms, used tissue paper…) make them look like trash cans — and they smell.

      Odd they only seem to be used in Washington DC, but only by, the NPS simply uses mulch around new trees. Take a short trek into VA and MD and you don’t see such silly things.

      If you can fill a bucket, you can water a tree that is well mulched. Mulch works the same way but better, same amount of water each watering with the added benefit of the mulch absorbing rain water for slow release. And mulch biodegrades and is less of an eye sore. Someone (Who dat?) made out with a great contract from one of the DC government — tax payers ultimately got stuck with another wasteful boondoggle from our corrupt electeds helping their cronies.

      • I’m not sure mulch works the way you think it does (absorbing and releasing water.) Recent advice is that most trees are over-mulched with big piles that actually steal water from the tree. The mulch does absorb water, but then it is lost through evaporation. But I’m not an arborist.

        • Agreed that trees should not be over mulched, but you’ve got a lot of people (including arborists at NPS and elsewhere) to convince with your argument. Did the ClimateRide from NYC to DC last week and curiously did not see one of these buckets around any of the new young trees in Manhattan’s lovely new green spaces or around trees anywhere in NJ, PA or MD. It would be nice if DC followed some best practices that were supported in other jurisdictions.

          Where else are these buckets used? Doesn’t water evaporate out of the clogged trash filled buckets; doesn’t the black color attract/conduct heat?

          First we had the green bags that create a moist unnatural micro climate around the base of trees which damages the bark. Then DC used the larger bags that did the same thing and were even uglier.

          It seems simpler just to have people water the trees directly as regularly as they would fill the buckets and the trees would be better off w/o the extra steps.

  • Two of those appeared on trees in front of my house, and disappeared a few weeks later. I have no idea who put them or who removed them.

  • I was thinking the exact same thing this morning. We are having a major mosquito problem in my neighborhood and buckets of standing water are a major contributing factor.

    Does rain water not “infiltrate” naturally? Seems like a moronic idea considering that trees have zero problem growing in the city or anywhere else on the East Coast for that matter without this…

    • Young trees need to be watered, particularly during our very hot summers. The ring is designed to let the water drain out over 3-4 hours. That’s not enough time for mosquitoes to hatch and develop. They need 7-10 days in standing water.

      • If that’s what they’re “designed” to do, then they don’t work.

        I have several on my street and when I wash them out and fill them with clean water, they drain within about 45 minutes.

        Most days, however, they are standing cesspools of scummy water, trash, leaves, and God knows what else.

    • Besides young trees needing to be watered, most street trees actually sit in very small strips of dirt open to the sky and therefore don’t receive rain in gentle pitter-patters on soil that their roots can access. There’s a lot of fast-flowing runoff that gathers on our pavements, sidewalks, and gutters that either bypasses the tree boxes or floods them at a rate far too fast for the trees to absorb. Also, while DC seems to be using the buckets, another model is called a TreeGator ( and many cities use it.

    • They’re primarily for newly planted trees which need more regular watering until their root systems are established. A couple weeks without rain is enough to kill a young tree, even though it might not show it for a month or more. On streets where new trees aren’t shaded by older, larger growth or buildings this can happen really quickly.

      If you’ve got one with standing water on your block, they’re easy enough to clean out. Just lift it up off the ground and pour a gallon or so of water in. If the dirt doesn’t force itself out of the holes automatically just poke through with a pen. Takes maybe 15 minutes to do the block, then you have fewer potential homes for mosquitoes and happy healthy trees!

  • I thought it was a new type of Bundt pan!

  • Basically, all you have to do is set it down, wait for rain, and then – vuowala, you will have all the mesquitoes you could possibly want in only 11 days.

  • Anyone who has used one of these could tell you that they empty really quickly, so mosquitoes are a non-issue. Each time I fill the tub up on my street tree, I check to make sure the holes aren’t clogged, and when I pass by the tree I double-check that the water has been able to drain. These watering tubs are great for the young trees – mosquitoes are not an issue here.

    • and anyone who walks by them can confirm that they are often clogged with leaves, dirt, trash, etc. so they don’t always drain well. It’s a problem in my neighborhood, which had a case of West Nile a few years back (making me especially unhappy about mosquito bites). Luckily, I just found out today that my ANC ordered bags instead of the open trays for new trees in the area. The bags work just as well for allowing a bit of water at a time to infiltrate, and are less tempting for trash or bugs.

  • I have one for a tree outside my house and it tends to get clogged a lot so I have put the mosquito dunks in mine for the water the remains or water from rain.

  • You asked for help understanding the tree watering jugs. DDOT’s urban forestry folks place them around new trees to water them. The water drains out fairly quickly, and likely fast enough to not breed mosquitoes. There’s no conspiracy here- they do what they say they do.

    If, in the unlikely event you see one clogged and you feel oppressed/threatened/offended/irritated, I’m sure you’re welcome to take a few seconds to clean it out.

  • Perhaps they could include the anti-mosquito larva cakes with each pan.

  • alxindc

    The version with the green water sack that snugs around the base of the tree is somewhat better. Still perverted.

    • Even better are the “ooze tubes” that are like little inner tubes around the base. They release water more slowly so need less filling/attention than the green “gator” bags that are a couple of feet tall.

      Casey Trees has some excellent info about the need to water tress, but their website seems to be down at the moment. when it’s back up….

      • Bags, tubs, whatever, when the govt put these around the now dead trees at the Kennedy Rec Center in Shaw, the trees died, because none of the govt staff bothered to ever put water into them. The govt should set a better example; if DDOT can’t teach their own colleagues at DPR how to fill/clean the devices properly, they might need a better strategy.

  • They do fill up with water because they get shifted around and then when they aren’t flat enough on the ground, or full of trash they do get a lot of standing water. Total mosquito breeding ground. The bags are much better. I got three trees from casey trees and they come with the drip bags. Not attractive but seem to be getting the job done.

  • Adding a little bleach to the water should kill off the skeeters, but I don’t know if that would harm the trees too?

  • I was wondering this myself. Can’t set any holes in the base.

  • Emmaleigh504

    Well the twitter conversation about this post shows me that @DDOTDC has been taken over by assholes. It’s a shame, they used to be informative.

    • Taken over by assholes? I thought their responses were pretty funny, particularly considering this is A) a dumb question, and B) a question that was answered by multiple people in this comment thread already.

      • This isn’t a “dumb” question. I have water three trees in front of my house using these tubs, and people stop to ask what they are or how they work all the time. As for DDOTDC’s tweets, there’s a fine line between playfully engaging with constituents and being rude. For an organization that’s constantly asking people to adopt trees, they could have handled the question better.

    • Hi, emma I just took a look at the twitter feed and I thought their response was funny and informative! For them perhaps it’s a no-brainer but they did take the time to explain. So many govt twitter feeds are so stodgy or completely unhelpful.

    • Agreed. The tone of the response was completely unnecessary.

    • Woah, I just finally saw the DDOT tweet. That is so inappropriate. Whomever the douchebag is that was hired to manage DDOT’s Twitter account should be fired. Answering questions by the public is exactly the purpose of that account. Sarcasm and eyerolls at legitimate questions have no place in a government Twitter account.

  • Seems like the obvious solution here is for everyone to stop complaining and spend 15 seconds unclogging the holes. Problem solved!

  • BIG ISSUE: not mentioned yet, is that when these things inevitably get clogged up, they actually dry out trees! Basically they act as a rain shield that keeps the area directly around the tree dry as they capture rain that would have gone to the roots.

    I think these things should be put out to water the trees and then taken back and stored – not left permanently around the tree!

  • The city dropped off several of these in my neighborhood. Unfortunately they didn’t puncture holes in the bottom, so the water doesn’t drain. There are tiny “x” on the bottom where holes are supposed to be punched. Be sure to check before putting them in place and filling with water. They work great when installed properly.

    • I think you’re right. I went by the ones around my house (they were gone, they’re back), and they all had standing water. Shaking them didn’t drain them. I had to tip them to empty them, and my entire block is covered in these, all of them with standing water, none drained.

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