Frost Is Just Too Cool

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Frost makes tender foliage ugly fast.

Is it too late to warn about frost? After all the rain, the recent and sudden cold weather was quite a surprise. Fortunately, these recent frosts were relatively mild. This sort of weather is probably just enough to start to satisfy plants that require chilling through winter without causing too much damage to too many sensitive plants. So far, only the most sensitive plants, like angels’ trumpet, canna and left-out houseplants show symptoms of frost damage. (Cannas should get cut to the ground at the end of winter anyway.)

Doing without all frost sensitive plants would be too limiting. Lemon, avocado, bougainvillea, fuchsia and Australian tree fern would be off limits. Such plants are worth growing, as long as we understand the potential for occasional frost damage. Those that are too big to protect may sometimes need to get pruned for removal of stems that get killed by frost. In milder climates, such damage will be very rare. In cooler spots, damage is more common, and may involve a few tougher plants, like jacaranda.

Smaller plants that are sensitive to frost, such as jade plant, angel wing begonia and the various pelargoniums, can be grown in containers so that they can be moved to sheltered spots before the weather gets too cold for them. The most sensitive sorts need to be moved under a porch roof or eave, or maybe into a garage. More resilient plants may be safe under overhanging trees or against a wall. South or west facing stucco walls radiate a slight bit of warmth at night.

Frost sensitive plants that get too big for containers should be planted in sheltered spots, like below eaves or larger trees. If a severe frost is predicted, young plants can be protected by burlap, paper, trash bags or any convenient sheeting suspended above by stakes. Foliage that touches the sheeting may get frozen, but foliage within should be fine.

Foliage and stems that get damaged by frost should not necessarily get pruned away immediately. Although unsightly, the dead foliage insulates damaged stems below from subsequent frost. Besides, premature pruning can stimulate new growth, which is more sensitive to subsequent frost.

Horridculture – Tree Preservation Ordinances

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Padding should protect these London plane street trees from minor altercations with machinery that will be used to demolish the associated buildings and construct new buildings.

Much of my work involves inspection of trees to assess health, stability and structural integrity, and subsequent composition of associated arborist’s reports to document such assessments. These reports are necessary for the issuance of permits to remove mature trees within many municipalities. They are only effective for that purpose if they recommend and justify removal.

If there is nothing wrong with the health, stability or structural integrity of subject trees, removal might be justified for other reasons. For example, the removal of superfluous trees might be justified if it would promote healthier development of remaining trees. Trees that disperse roots that are beginning to damage adjacent infrastructure might likewise need to be removed.

It seems like it is too much to be concerned with for something that property owners should not need permission to remove from their own property. For what people pay for property here, they should be able to do whatever they want to with it. However, mature trees are considered to be assets to their respective Communities, and components of the collective urban forests.

These majorly and justifiably controversial concerns are actually not the the only difficulties associated with municipal tree preservation ordinances.

While a young coast live oak in the extreme corner of my garden was not quite big enough to require a permit for removal, I asked the next door neighbor if he would like it to be removed before the roots damaged his driveway. I explained that if we waited any longer, the tree would be protected, and that a permit to remove such an exemplary tree would not likely be issued.

Tree preservation ordinances are often the motivating factor for the removal of trees before they get big enough to be protected! I was fortunate that my neighbor wanted my oak to stay.

Prune

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Prune trees get planted bare root.

Does anyone remember when champagne produced in California was formally classified as ‘sparkling wine’? ‘Champagne’ is a technical classification for that which originates from the region of France for which it is named. That makes sense. The technical classifications of prune and plum formerly made sense also, even if not universally understood. Reclassification in 2001 ruined that.

Prune, Prunus domestica, is primarily a European freestone fruit. (The pits of freestone fruits separate from the ripening flesh.) They have firmer flesh than plum, so are more practical for canning and drying. They also have higher sugar content, so might be dried without sulfuring (which prevents molding). Darkly purple and rather oblong fresh prunes are less popular than dried prunes are.

Plum is primarily a Japanese cling fruit. (The pits of cling fruits remain firmly adhered to ripening flesh.) They are softer and juicier than prune, and contain less sugar, so are not as efficiently pitted and dried without sulfuring, or canned. Larger, rounder, more colorful and more richly flavored plums are instead best fresh. They might be bluish purple, purple, red, ruddy orange, yellow or green.

Nowadays, all prunes and plums are known collectively as plums. Dried prunes are just dried plums.

Planting Bare Root Stock Properly

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Bare root roses bloom next summer.

Most of the advantages of bare root stock are obvious. Bare root stock is less expensive and easier to work with in regard to installation and pruning to a desired form. What some of us may find difficult to understand is that it actually gets established into a new garden more efficiently than canned (potted) nursery stock does. As incredible as it seems, there are a few simple reasons why.

Instead of dispersing roots within the confinement of cans, bare root stock disperses roots directly an extensively into the soil into which it gets planted. Their initial deficiency of roots encourages them to do so quickly. Roots of canned stock must recover from confinement. Their new roots may be hesitant to leave the comfort of the extra rich medium in which their original roots developed.

The holes dug for planting bare root stock need not be much wider than the roots can be spread apart, and no deeper. If too deep, newly planted stock will sink as the loosened soil below settles. Grafted plants must not sink enough for their graft unions to be below grade. A cone formed of firmly pressed soil at the bottom of a planting hole can be useful for spreading roots out evenly over.

Rich soil needs no amendment. If compost is added to loosen dense soil, it should be as minimal as practical. Too much amendment will tempt roots to stay close rather than dispersing remotely. Fertilizer is not necessary immediately after planting. However, because the soil does not stay very cold here, and roots start growing before spring, mild fertilizer can be applied shortly afterward.

Finally, most bare root stock should be groomed and probably pruned after planting. Fruit trees are often sold with only minimal prior pruning. Superfluous stems function as packing material that buffers the ravages of transportation, and also provide more options for preliminary structural pruning. Aggressive pruning of plants that benefit from it concentrates resources for growth in spring.

Deodar Cedar Migration – Update

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Reassigned deodar cedars have adapted to their new landscape.

Reassignment is in season right now. The brief article about it that posted yesterday links to three other related articles. We have done quite a bit of it here, and intend to do a bit more for useful plants that happen to be in the wrong situations. It should be done before winter ends, to take advantage of both natural dormancy and cool winter rain that settles transplanted roots.

Most plants that get reassigned get dug from situations where they can not stay, and transplanted directly to where they will likely become assets to their respective landscapes. Those that do not get transplanted directly into other landscapes get canned and housed temporarily in the nursery. Some need to recover. Some must wait for landscapes that can accommodate them.

Some reassigned plants are feral descendants of exotic (non-native) species, that grew from self sown seed. Others were originally planted intentionally, but for one reason or a few, are no longer appropriate for their particular situations. Some are overgrown perennials that needed to be divided. On rare occasion, we encounter specimens of native species that get reassigned.

Deodar cedar that were reassigned slightly more than a year ago recovered from the process last spring and summer, so should grow this year as if nothing ever happened. Unfortunately, several were inadvertently killed when the roadside weeds and grasses that they grow amongst were cut down. In other areas, too many superfluous specimens survived, so must be culled.

Those that will be culled out need not go far. They can be plugged back to replace those that were mown down. The second process will be easier than the first. Superfluous specimens were reassigned because we expected nearly half to not survive the process. Except for those that were mown down, almost all survived. If not culled, they will get too crowded in just a few years.

There are plenty more where they came from. The four parent trees are prolific with their seedlings. We can not reassign all of them to other landscapes, and should not waste resources on canning specimens that will not likely be accommodated within any of our landscapes. I will likely can many of them, but not for here. They may become GREEN street trees in Los Angeles.

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The four reassigned deodar cedars in this small space are not easy to see in this picture.

If it seems as if the reassigned deodar cedars are too close to surrounding trees, it is only because the surrounding trees will be subordinated and eventually removed as the deodar cedars grow big enough to replace them. One is a dangerously disfigured sweetgum with roots that are displacing pavement above. Two others are disfigured and deteriorating California bay trees.

Reassignment

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African iris are happily rehomed.

African iris, Dietes bicolor, that I mentioned three weeks ago were finally installed into a new landscape. It may not be permanent. They may need to be relocated again if they happened to land where two of four birch will be installed as the landscape is slowly assembled before winter ends. The installation was done hastily before the last storm delivered a good dose of rain.

It could not be delayed any longer. These African iris had been divided and groomed so long before they were featured on the fourteenth of December that they were likely to succumb to rot or desiccation if installation was delayed any longer. They soaked in buckets of water for days at a time, and were then left to drain for days at a time so that they would not soak for too long.

I do not remember how many times I repeated the process. I knew it was getting risky. Surprisingly, by the time they were installed, only a few of the worst of the rhizomes were beginning to exhibit negligible indications of rot. Now that they are in moist but fluffy and well aerated soil, they can recover and begin to disperse new roots, even if they must be relocated again later.

If relocated again later, the process will be fast and direct. They will get dug and plugged within minutes. Compared to alternated soaking and draining for more than a month, it will be easy.

The formerly feral birch that will eventually be added to this landscape are also being reassigned. Of nine that were removed from another landscape in the neighborhood, five were already plugged directly into a landscape across the road. The other four were canned temporarily until we determine where they will fit into this new landscape. They will arrive before winter ends.

Lauristinus that formerly inhabited this area were already being reassigned as hedges in other landscapes before we planned to reassign extra African iris and feral birch to this landscape. A few got canned to replace any that do not survive the process. So far though, all have not only survived where they were reassigned, but were growing happily before the weather got cool.

Six on Saturday: Two Too Many Redwoods

 

Redwoods are such admirable trees that no one wants to cut any of them down. On rare occasion, it becomes necessary to do so. Seedlings sometimes grow in situations where they can not stay. They might be too close to buildings or other infrastructure. Sometimes, they are merely in the process of crowding other important plants in the landscape. That was the problem with the young redwood pictured here, and another just like it.

1. There it is, an exemplary specimen barely left of center. The problem was that it would have crowded other trees if left to grow. The dogwood to the left is feral too, but will not get too big.P00104-1

2. This juvenile tree had been cut off at the ground, and regenerated. This meant that I expected it to be more firmly rooted than it would have been if it had not experienced such trauma.P00104-2

3. What a surprise! Roots on one side had already been severed by earlier excavation for a drainage pipe. As I cut a few more roots on other sides, this unfortunate young tree just fell over.P00104-3

4. There were enough roots remaining for this tree to survive if there had been someplace to put it where it could have been irrigated and guyed until it recovered and dispersed new roots.P00104-4

5. Guying would have been difficult though. The young and slender tree was just too tall and flimsy for any downward tension applied by guys. Sadly, this young redwood was not salvaged.P00104-5

6. This is really why I was here. Besides removing two feral redwoods, I dug two Japanese maples that had been stagnating in the landscape for years, and canned them to hopefully recover.P00104-6

This is the link for Six on Saturday, for anyone else who would like to participate:

https://thepropagatorblog.wordpress.com/2017/09/18/six-on-saturday-a-participant-guide/

Knife-Leaf Wattle

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This wattle sports texture with color.

Even without the bright yellow staminate flowers (fuzzy with prominent stamens) that bloom in late summer or autumn, the grayish foliage of knife-leaf wattle, Acacia cultriformis, is still striking. It contrasts nicely with dark green foliage of pines, redwood and ivy. What seems to be small triangular leaves are actually ‘phyllodes’, which are modified petioles (leaf stalks) of vestigial leaves. They are about half an inch to an inch long, and neatly arranged on stiff stems.

Mature trees do not get much more than ten feet tall, and grow slowly enough to be kept even shorter. They can tolerate a bit of shade from larger trees. However, they bloom more profusely with better exposure. If the pollen is not a problem, the flowers are nice for cutting. So is the foliage, which is complimentary to many other cut flowers. Like almost all acacias, knife-leaf acacia does not require much water once established.

Bare Plants With Bare Roots

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Dormant plants do not miss soil.

Knowing how colorfully bulbs will eventually bloom can initially make planting them disappointing, since there is nothing to see for all the effort. Planting bare root plants is not much more rewarding. The bare stems are a bit more proof of the effort, but will do nothing until they break dormancy in spring. Now that Christmas trees have vacated nurseries, bare root plants will be arriving, and will need to be planted before winter ends.

As the name implies, bare root plants have bare roots, without the soil they were grown in. Better equipped nurseries ‘heel in’ bare root plants in moist sand, which simply means that the roots get buried temporarily. When purchased, the plants get pulled from the sand and wrapped for the trip to their new home garden, where they get planted permanently into real soil.

Alternatively, bare root plants can be prepackaged in bags of moist sawdust. They only need to be removed from their packaging and sawdust before getting planted into the garden. Mail order plants, including plants purchased online, often get packaged even more simply, with a damp bag around the roots, maybe with a bit of gel or damp paper. The plants are safely dormant, so are not even aware of what is going on.

The main advantage of bare root plants is that they cost about a third of what typical nursery stock in heavier cans of media (soil) cost. Because they are so much less cumbersome, several bare root plants can be purchased at a time, and brought home in a small car without much effort. Since they lack the luxury of the soil they were grown in, they immediately disperse their roots directly into the surrounding soil.

Roots of bare root plants should be spread away from each other at planting. Soil amendment is nice, but should not be so copious that roots will not want to disperse outside of the amended soil. Even if rain is expected, newly planted bare root plants should initially get soaked so that soil settles around the roots. Grafted plants should be planted with the graft union above grade.

Fruit trees such as apricot, cherry, plum, prune, peach, nectarine, almond, apple and pear, as well as roses, are the most popular of bare root plants. Flowering crabapple, flowering cherry, poplar, willow, lilac, forsythia, wisteria and grape are also available.

HAPPY NEW YEAR!!!

P00101-1January 1, 2020! The first day of the Twenties!

The flora in our gardens north of the Tropics must think we are crazy for making such a fuss about it while they are trying to sleep. Even flora south of the tropics does not understand. All flora everywhere is more concerned with how the seasons change according to the position of the Earth around the Sun. Precise dates, times and numbers are meaningless.

It sort of seems odd to me that within each time zone, it is the same time and date both north and south of the Equator, but the seasons of each side are opposite. Today started in sparsely populated regions of the Pacific Ocean, worked its way through Australia earlier, and is somehow still the same ‘today’ that is here now. Yet it is winter here, and summer to the south.

Now, if January can be in the cool time of year here, and the warm time of year in Australia, it seems to me that winter could be both the cool season here, and the warm season in Australia. If the dates are the same, it seems like the seasons should be too. Alternatively, if the seasons are half a year early or late in opposite Hemispheres, it seems like dates should be too.

According to such logic, it could be either winter or July 1 in Australia and elsewhere south of the Equator right now! . . . But would that be July 1 of 2019 or 2021? Too many technicalities!

Well, it is more than the flora in the garden is concerned about anyway. It is winter here now, and summer south of the Equator. It is the beginning of January everywhere that the Gregorian calendar is used, north and south.

HAPPY NEW YEAR!

Note: ‘Horridculture’ will resume next Wednesday. It did not seem appropriate for the first day of 2020.P00101-2