The best mulch and where to get pine staw

Shred autumn\'s leaves for a great compost. Tomatoes, roses, lilacs and fruit trees and especially benefit from this type of gardening. (Thinkstock)
Crack a beer to deter slugs

wtopstaff | November 14, 2014 7:39 am

Download audio

Mike McGrath,

Best mulches for veggie gardens

Jim in D.C. writes: “I know you’re a fan of using an inch of compost to mulch tomato plants. But how about zukes, cukes, peppers and eggplant – what’s the best mulch for them?”

Compost is the best mulch for any plant, Jim, but we gardeners never seem to have enough to do it all. That’s why I stress that disease-prone plants like tomatoes, roses, lilacs and fruit trees get first crack. They absolutely require 1 to 2 inches of compost on the surface of their soil to keep illness at bay.

If you’re blessed with more compost than that, move on to your other plants, especially giving the nod to any with disease problems in the past. When you run out of compost, use shredded leaves, pine straw or other non-wood mulch.

Shredded fall leaves are especially good as a mulch around edibles. The leaf cover provides the perfect habitat for earthworms, who will move in and feed your plants for free with their nutritious castings.

Where’s the Pine Straw?

Bruce in Leesburg is one of many listeners failing to find what I recently called “the most popular mulch down South.” He writes: “I’ve been searching nurseries and home improvement centers in Northern Virginia for pine needle mulch. Do you know where I might be able to find some?”

The current shortage of pine straw mulch may partially be my fault, Bruce. Several garden centers told me they had runs on their stock after I mentioned it as a great alternative to nasty wood and bark mulches. And restocking may take a while – the suppliers have to be careful not to over harvest this natural material from the forest floor.

Luckily, a somewhat similar bagged product is currently available called pine fine, which one presumes is the smaller material found at the bottom of big batches of pine straw. I was given a bag to sample and am pleased to report that it has a very pleasant, slightly piney smell and the consistency and color of compost, which makes an excellent mulch. (Listeners: If you give pine fine a try, be sure and tell me what you think.)

Another alternative I was offered is cocoa hull mulch, which had been hard to find for awhile but now appears to be back in bulk. That bag went to my neighbor, who had fond childhood memories of the light chocolate scent imparted to her landscape when her parents used it. Note: Don’t use cocoa hull mulch if you have dogs who eat everything in sight. It does contain the same compounds as chocolate, which can be dangerous to dogs when ingested.

Newly planted tree? Take a lesson from the White House

Until it was snapped in a storm, the same living evergreen served as the National Christmas Tree at the White House for 30 years. Its replacement tree, however, barely made it one year and had to be cut down on May 5. National Parks Service spokesman Bill Line blames a spring planting that was followed by the hottest summer in history and plans to hold off on installing the replacement tree until October of this year.

That’s an excellent idea. The survival rate of big trees planted in the fall is much higher than for spring plantings. So if you have a newly planted tree that went into the ground this spring, be vigilant. Water it deeply by letting a hose drip at the base of the tree for several hours right after it goes in, and continue to water it deeply at the base every week we don’t get rain. Make that twice a week if summer is really hot and dry. Failure to adequately water during the first year in the ground is the biggest cause of new tree death.

The second biggest cause of premature death is planting a tree whose roots are still wrapped in plastic or burlap. Unfortunately, video of the planting suggests that this may have happened with the White House tree. This is such a serious concern that newly planted trees with wrapping still around the roots should be dug up and the wrappings removed (from the roots and the hole), despite the additional transplant shock this could cause.

The other big no-nos are planting the tree too deeply and applying any mulch deeper than 2 inches. If you can’t see the root flare above the soil line, it’s too deep. Yes, all those ‘volcano mulched’ trees will die an early death. And if you apply mulch deeper than two inches, rainwater won’t be able to reach the roots.

Severed stems? Have a beer

Frank in Hamilton writes: “My broccoli was doing fantastically until I looked at it today and saw that something is cutting it off about 3 to 4 inches above the ground (the plants were up to about 10 to 12 inches high.) The ground is wet and muddy from the rain but I didn’t see footprints of anything like deer, groundhogs, or rabbits. The cuts are clean, almost like a scissors was used. Any thoughts?”

Two thoughts, Frank: Cutworms or slugs. Cutworms are caterpillars that live just under the soil line and sever seedlings at night. Slugs also do their dirty work in the dark and often leave similar evidence behind.

To diagnose the demon, put small containers of fresh (not stale!) beer around the plants this evening – not in the morning. If slugs are the problem, your traps will be filled with dead drunken ones in the morning. Then spread a non-toxic slug bait like Sluggo or Escar-Go around your plants. The iron phosphate in the bait is deadly to slugs but doesn’t harm anything else.

If no slugs are found swimming, cultivate the soil and destroy any cutworms you encounter. And protect the remaining plants with ‘cutworm collars’ – soup cans with both ends removed inserted into the soil an inch or two deep around each plant stem.

Herbicides kill people, not violets

Chris in Fairfax seems to be trying for the Darth Vader Garden Award. He writes: “I have a well-established yard that is regularly fertilized and treated with herbicides. However, I can’t seem to get rid of the wild violets that are rampant in my lawn. I thought that the usual broadleaf weed killers like 2-4, D and MCPP would take of the situation, but to no avail. Do you have any recommendations?”

Yes, Chris. First, step away from your sprayer of death. Further away!

Second, take a chill pill, man. They’re violets, not violent offenders! Pretty little flowers are not a threat to your family or home, and toxic sprays (which ARE a real health threat) are not the answer no matter what, because no herbicide affects wild violets. That’s why the flowers weren’t listed on any of your herbicide labels – there is no herbicide labeled for use against violets.

If you must be rid of them, you would begin by caring for your lawn correctly. That means never cutting the grass lower than three inches and only feeding the turf in spring and fall – never summer. I suspect your implied over-feeding of your turf and declared over-herbiciding is working in the violets’ favor.

After your grass is healthy and better able to compete with the violets, begin removing the existing clumps. Working small areas at a time, soak the soil well and sloooowly remove the clumps by hand-pulling at the soil line. The ideal time for this chore would be late August, when you can successfully reseed those areas right after the clumps are out.

WTOP Reporter Max Smith contributed greatly to the White House portion of this story. Thank you, Max!

Follow WTOP on Twitter.

(Copyright 2012 by WTOP. All Rights Reserved.)

Advertiser Content