Some scientists predict an increase in natural disasters as a result of global warming. But somehow I think something else is responsible for all the volcanoes I see erupting in my neighborhood.

‘Volcano’ is the term coined for that mound of mulch that folks pile around a tree this time of year. Even though all the credible references advise against this, it somehow seems to be very popular. I drive through developments in which landscapers have generously heaped the mulch into a nice pyramid around every tree.

After spending a fair amount of money on new trees, you would think a homeowner would want to protect that investment. One of my neighbors recently built a series of volcanoes around the trees throughout his yard. It looks kind of cool, but just like Mount Vesuvius, these volcanoes can be deadly. That pile of mulch heats the base of the tree and holds moisture up against the bark. Not only does this encourage pests and diseases, but the tree responds by sending out new roots into that pile of mulch. Instead of spreading outward, these new roots grow inside the pile and over time can girdle the tree as they expand.

The International Society of Arboriculture recommends mulching tree root zones to help retain moisture in the ground and act as a weed barrier. But to avoid decay, disease and pests, ISA calls for mulch to be kept one to two inches away from the base of the tree. So a good gardening practice after mulching is to go back and sweep away any that might have piled up on the tree flare.

The trees will thank you.

Violaceus euphonia looking for nectar in the avocado tree (Persea americana)

     This time of year, there are a few trees in the Costa Rican exhibit that like to drop some or all of their leaves. It can be kind of embarrassing- and messy- to have trees in a tropical glasshouse without any leaves, but it is completely normal. Many tropical trees lose many, if not all, their leaves for a short period this time of year before putting out a new set of leaves.

    Also, not all of them are completely naked because this is also the time many trees, like the avocado tree on the left, start to flower. It makes perfect sense that trees would flower when there are fewer leaves in the way. Having no leaves when in flower greatly increases the visibility of the blooms so they can be easily seen by pollinators. The nectar feeding birds and butterflies have certainly noticed that the avocados are in bloom and have been spending a lot of time in these trees. I can already see the avocado fruits starting to form.

     In Costa Rica, December to March is known as the "dry season," and this is when many deciduous and semi-deciduous trees and plants lose their leaves (the rest of the year is known as the "green season" or "rainy season"). The sparse canopy in the dry season can reveal plants and blooms that may have been hidden during the green season and can make it easier to spot animals. The rainforest canopies are also painted with color from the showy blooms of trees like the two Tabebuia species pictured below.  Tabebuias are dry season deciduous trees that bloom while completely leafless shortly before leafing out.

Tabebuia impetiginosa	Tabebuia aurea

Posted by Nate Tschaenn 

Mid-winter at Cleveland Botanical Garden is a time to look up.  Vivid autumn is a faded photograph lost in mom’s dresser drawer, and the twinkle of the holidays is now an unplugged string of lights lying in the snow. The days are still weak but growing stronger, and the sky is a drama of frozen smoke and clouds like anvils and granite.

The leaves are gone and the little grove is laid bare. Our dozens of big trees, remnants of Wade Oval’s once-forest of oaks and tulips, now dare to throw their crosshatch of flying beam and lintel against the framing sky.

One tree in particular catches my attention.  It is the red oak (Quercus rubra) growing in the circle of lawn near the C.K. Patrick Garden. There is no better specimen in Northeast Ohio.  From a sturdy buttress of exposed roots, it bends skyward on a massive, branchless trunk.  The bark is steely and segmented like armor plate.  At about 45 feet above the turf, it abruptly sends out three thick limbs, and then a few feet higher, several more. They proceed to radiate upward, divide and sub-divide in patterns repeating the stronger patterns beneath them, and end in pencil-twigs and rocket-buds, 70 feet aloft; a crown that offers royalty to the surrounding grove. 

Red oaks are perhaps the most common deciduous tree in our local upland woods.  But familiarity does not breed contempt.  Their numbers provide endless variation to the red oak theme.  For instance, the bowed trunk that our sample displays is a tendency throughout the species — like a gentle conceit — that is fun to notice.  Sometimes, it is rakish and exaggerated on that odd individual daring to grow out over the brink of a local ravine.  Couple this trait to the elbowed, muscled, sinewy limbs, and the red oak becomes so distinctive that a spotter can identify a red oak against the far horizon. 

Oaks as a group number over 700 species, and circumnavigate the North Temperate Zone. They are then split into the red and white oak tribes. Ours is in the red tribe, which means that its leaves have pointed, minutely-bristled lobes instead of rounded lobes; and that its acorns take two growing seasons to mature on the branch instead of just one.

Red oak acorns look like velvety “heads” sporting jaunty berets. They fall to the ground in October, immediately germinate and issue carmine-red tap roots, pause for the winter, then resume business next spring.  This was a good year for acorns (every several is a cyclical “mast” year), and it was like walking on garden marbles for awhile there. But today, most of ours are reduced to husks heaped at the base of the trunk, complements of hungry fox squirrels. 

Please don’t surrender these days to the television.  Look up through our Garden and witness the beauty and strength of the red oak revealed, as it stands against Cleveland’s dramatic winter sky. Too soon it will be April, and so many leaves attendant.

Posted Mark Bir

 I know we are violating some of the basic rules of pruning. But sometimes we push plants to do things out of the ordinary. In this case, we are dealing with a row of plane trees in a formal terrace garden. These trees form the western boundary of the Garden’s Geis Terrace and are deliberately topped and shaped into a rectangular hedge. One of the horticulturists here calls them a “hedge on stilts.”

I feel compelled to add “don’t try this at home” — unless you are committed to regular pruning. Our eight trees took 16 hours with a hand pruner this spring.  And I’ll be going back up this summer to shape and snip any wayward growth.  The middle of the tree can be climbed but the edges are all done on ladders.  I couldn’t do this with a pole pruner because I had to be up-close-and-personal with each cut in order to re-direct the growth at the ends of branches into a plane.   Each snip was made about a quarter of an inch after a bud that was pointing in the desired direction.

 

The Latin name for Tulip poplar is one of the most melodius-sounding names in botany. Liriodendron tulipifera.  It can be translated as: “Tulip-bearing lily tree.” The name refers to the large flowers, which resemble a creamy, green and orange tulip with a conical tower of seeds in the center.

After all I’ve done for them!

In this case, it is Crown Gall.  This bacterium may have come with the plant when it was purchased five years ago. It reduces the vigor of the plant and forms unattractive tumors on the branches. Most experts agree that there is no effective remedy. But I tried one anyway. 

Last year I simply cut them off. They grew back. So this year I tried a product called Gallex. I cut them off again and liberally brushed on this goop that looked like Pepto-Bismol. I even used an air compressor to blast away some of the soil so I could examine the roots to see if they had any galls that needed treatment. We’ll see if this product takes care of the problem. I would be interested in hearing from anyone that has successfully eradicated crown gall from a plant.

 …that is if you want them to survive. I’m not sure why so many trees are improperly planted and mulched. The landscapers I talk to all seem to know better. But somebody is out there suffocating our trees.

 

• New trees need to be planted at a height that shows off the base of the trunk as it flares toward the roots. This maple is planted too deep and is showing signs of decay.  Here are a few tips to ensure proper planting. 
• Scrape away any additional soil the nursery may have added to the root ball until the flare is exposed.  This newly planted oak had a good two inches of compacted soil under the burlap wrap that was above the flare.

 

• Plant the root ball on firm soil to prevent the tree from settling or sinking into the hole. 

• Over the years if you are adding compost or other soil amendments to your beds, don’t spread them all the way up to the tree. And by all means, don’t pile mulch around the tree. 

Trees that are planted too deep or have soils or mulches piled around them end up having to send out newer and higher roots that are closer to the surface. This stresses the tree and over time these can girdle the tree as they expand. Plus, soils and mulches piled around the trunk are an invitation for pests and fungal problems. It is no wonder that some studies show the average life of urban trees is only seven years!   Improve your chances by making sure your tree doesn’t look like a telephone pole that has been sunk into the ground.  Instead give your tree that majestic trumpet flare to solidly anchor it for decades or even centuries to come.

I’ve always heard the benefits of planting a living fence instead of constructing one out of wood or metal. Hedges are adaptable and can be pruned to a variety of sizes and shapes. Plus, they never need to be painted, which is a big plus as far as I’m concerned. I experimented last year with a hedge alternating firethorn (Pyracantha coccinea) and privet (Ligustrum amurense). The leaves are very similar but the branching structure, flowering and fruiting seem to provide a nice contrast. I planted them in a row about 15 inches apart and will do some pruning at the base to ensure they branch out nice and low so my dog can’t squeeze under anywhere. Plus, I want to make sure I get a wide base so I can angle it back toward the top middle to maximize sun exposure. Ultimately, this could grow to be a 12 foot hedge. But I plan on keeping it in the 6 to 8 foot range.

I am also experimenting with European hornbeams (Carpinus betulus ‘Fastigiata’) to create a living arch. I saw a picture of one that was trained into an arch by pulling it all the way over and staking the top to the ground.  I didn’t have the budget for a tree that size, so I bought two smaller ones that can grow together at the top of the arch.  Unlike some of the bending going on under the 18 inches of snow we got this past weekend, I’ll gradually start bending the hornbeams in the spring. I am not yet sure what I’ll use at the top to make the connection. I am not too worried about whether or not the trees will bend correctly so long as I don’t try to force it too fast. 

Posted by Bob Rensel