Unplanned Green Roof

p90106The last green roof that I wrote about was planned, although not in a typical manner. https://tonytomeo.com/2017/11/25/green-roof/ It is still my favorite green roof. Otherwise, I am none too keen on the fad. Very few buildings benefit from green roofs, and green roofs really do take more work than conventional landscapes in the ground.

The sort of green roof pictured here was most certainly not planned. It could have been the result of a an uncleaned gutter. All sorts of weeds can grow in the damp debris that can wash off of roofs, particularly in damp and foggy coastal climates where moisture so often drips from the edges of roofs. This gutter is just a short distance from the beach in Santa Cruz. The willows in the San Lorenzo River are next door.

Knowing what I know about this particular type of willow, I would guess that the cleanliness of the gutter, or lack thereof, was not really the problem. These aggressive willows can germinate in the slightest bit of debris, even under a single leaf that did not get rinsed or blown away fast enough. Once germinated, their finely textured roots are experts at clinging to anything that might otherwise get rinsed away. If there is not enough debris and dirt for them to grow in, they simply collect their own. Now that it has started the process, it will continue to collect debris and expand its root system until it gets removed or ruins the gutter. It seems to have already collected enough debris to share with a few grassy weeds nearby. It is mostly dormant now, and might have defoliated in the rain since this pictures was taken a few days ago. However, if it stays, it will resume aggressive growth as winter ends.

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Falling Leaves Get Into Everything

51028thumbEven if they had been clean since they were emptied out last winter, gutters (eaves-troughs) near deciduous trees will eventually need to be cleaned again as they collect falling leaves through autumn. Leaves may continue to fall for several weeks, and will fall more abundantly as they get dislodged by rain.

Too many fallen leaves clog gutters and downspouts. If too much debris is left in downspouts for too long, it rots and settles so that it can be very difficult to dislodge. If rainwater can not adequately drain through gutters and downspouts, it can only flow over the edges of gutters. The falling water can erode the ground below, and splatter mud onto nearby walls.

This may not seem like much of a problem, but the reason that gutters and downspouts drain rainwater to the ground gently is to keep the walls dry and clean. Damp walls are likely to rot, especially if water splatters into basement vents. This is why early American homes that lacked expensive gutters were often outfitted with dense ‘foundation’ shrubbery or perennials to soften the splatter.

Leaves that accumulate in the valleys of the roof (where perpendicular slopes meet) should also be removed. Debris can also collect on the upslope side of a chimney. Homes with room additions have more awkward spots to collect debris than unaltered homes. Flat roofs and parapet roofs are of course very likely to collect debris under trees, and may need to be raked more than once.

Vines should not be allowed to climb onto roofs. They can tear apart roofing material, collect debris, and promote rot. Likewise, limbs of trees and large shrubbery should not be allowed to touch roofs, gutters, or even walls. Their motion in the breeze is abrasive to shingles, gutters, paint and siding. They can literally grind off shingles and break terracotta tiles.

Tree limbs should also be kept clear of chimneys. Even during rainy weather, hot exhaust from a chimney can dry and ignite limbs that get too close. Pine, cypress, cedar, and palms with beards (accumulated dead fronds) are very combustible.

Gutters And Chimneys Need Attention

71101thumbThere is no time that is best to clean the gutters on the eaves. They should probably be cleaned early before the debris within them gets dampened by the first rains. However, they will only need to be cleaned out again after more foliage falls. If cleaned only after all the foliage falls, they will be grungier, and there will be potential for some of the debris to flow into and clog the downspouts.

Most of the fresh leafy debris that fell recently is relatively easy to clean out. Debris that has been accumulating through the year will be more decomposed and settled in. Evergreen trees are somehow messier than deciduous trees. They drop smaller volumes of debris in autumn, but they drop the rest throughout the year. Deciduous trees drop all their foliage within a limited season.

That certainly does not mean that deciduous trees can not make a mess. All that foliage has to go somewhere. If the weather gets cool slowly, foliage falls slowly, and for a longer time. Some deciduous trees innately defoliate slowly, and may even wait all winter to finish. Fruitless mulberry, tulip tree and poplars typically defoliate efficiently, making a big mess that gets cleaned up once.

Flat roofs that lack gutters collect debris too. So do the spaces behind chimneys and in roof valleys (where the slope changes direction). Even if this debris does not interfere with the function of gutters and downspouts, it promotes rot in roofing material. Trees and vines that touch a roof are likely to be abrasive to roofing material if they move in the breeze, or hold debris against the roof.

Trees and vines must be kept clear of chimneys, not only because they can interfere with ventilation, but also because they can be cooked by exhaust from the fireplace below, and ignite! Fan palm beards (dead foliage that accumulates on trunks), pine, cypress, spruce and cedar are particularly combustible. Clinging vines can separate brick from mortar, which is another fire hazard.

Working on the roof and gutters is of course potentially dangerous. It might be best to get a professional for these sorts of jobs, especially if trees need to be pruned. While that is being done, there is plenty of raking and other gardening for us to do (without a ladder). Raking leaves is an important job too, since fallen leaves can shade out lawn, ground-cover and flowering annuals.