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Saturday, February 16, 2013

How To Thicken a Newly Planted Thin Lawn

Q. I started a new lawn last fall and I am very happy with the results.  I want to re-seed the areas that came up a bit thin. When and how should I do that so I don't damage the rest of it? I was also considering doing an aeration soon, as I always did every winter at my previous home with great results. Should I aerate this younger lawn?
It is common for newly seeded lawns to be a bit
"thin" at first, but larger open areas should be reseeded.

A. I understand your concern about the lawn being too thin but this can oftentimes be the case in a new lawn, particularly with cool season grasses like fescues. Fescues fill in voids between seedlings primarily by "tillering".

            They do not have the capacity to fill voids with strong rhizomes (underground stems) and stolons (above ground stems that lay on the soil surface). Frequently these are more associated with the warm season grasses such as bermudagrass, zoysia and St. Augustine.

            Tillering is the "sprouting" of side shoots from the base of the plant. As a grass plant emerges from the seed it shoots up one stem with associated leaf (‘mono’ ‘cotyledon’ or one leaf). This single stem with one leaf that eventually sprouts side leaves along the stem will grow very tall before it sends up side shoots unless the tip of this single stem is cut off. This is done by mowing (prior to lawn mowers it was done by animals eating the grass or grazing).

            Once the single stem has been cut off, the plant kicks into a survival mechanism and sends up side shoots (tillers) around the central single shoot. The side shoots occupy space around the central shoot and begin to fill in the voids between germinating seeds.
Tillers are side shoots that come from the base of the grass plant such as
this Poa annua bunchgrass.
            It is very natural to have these voids or open spaces around the seedlings for quite a long time unless we "graze" on the plants with our lawn mowers. So just by cutting or mowing the lawn we will encourage the lawn to get thicker by individual grasses "tillering".

            This is further sped up with a little bit of nitrogen fertilizer applied every few weeks, warm temperatures and regular waterings.

            Most lawn weed seeds respond to sunlight (they germinate when they "see" light). So quickly filling the spaces between grasses by tillering helps to reduce weed invasion in new lawns.

            Weed seeds like to germinate when soil temperatures hit about 50 to 55 F which would be in early to mid-February or perhaps sooner in real warm microclimates. So it is important to get the grass up and shade the soil surface as soon as possible in the spring.

            In fact, I prefer fall lawn seeding because of weed problems and fall and the following spring weather gives the seed a double dose of good weather for establishment.

            However, if you feel the distance is still too far apart between these seedlings then I would use the exact same seed and lightly seed in these areas and lightly cover the seeds with topdressing.

            If you want faster germination, soak the seed in cool water for several hours (not overnight or you will kill them) and then dry them long enough to dry their surface so they can be spread easily.

            Do not dry the entire seed out or you will kill the seed. Once they are surface dry you can spread the seed and you will save yourself a day or two of germination time. Fertilize lightly every couple of weeks and mow as soon as you can cut off 1/4 of the length of grass. Do not pick up the clippings but let them compost back into the soil unless it is loaded with weeds.

Saving Space in a Small Backyard With Multiple Trees in a Hole

Q. I'm going to see if I can do a multi-tree planting (three peaches in one hole) and espalier some along a south-facing wall.  Then again, now that I've seen some more of Dave Wilson's photos (http://www.davewilson.com/homegrown/BOCpix/espalier.html ) for espalier examples, I don't think I have the space to plant three trees in one hole. That seems to be for more open areas. Perhaps best to plant three different types of fruit trees that bear fruit at different times over the summer so we'll always have something
Three trees planted in one hole, the third year and before summer pruning.
Anyway, can you recommend any places where I can order small quantities of fruit trees? Shipping with Peaceful Valley (I ordered two bare roots last year and they didn't make it through the summer) puts them in the same price range as buying locally, where's there's less selection.

A. I want to handle one point at a time. The space needed for two, three, four or more trees planted in the same hole is about the same space required for one of these trees alone. The size can be kept to about a diameter of eight feet or possibly a bit less with aggressive winter and summer pruning. On apples it will require that they are on a semi-dwarfing rootstock such as M111.

            Pruning to maintain multiple trees in a single hole is aggressive and relies on the horticulturist doing the pruning to maintain separate spaces for each tree and that the trees are not allowed to invade or in any other way dominate the space allotted. This also requires that you select trees which have similar vigor to place in the same hole.

Three trees planted in one hole after summer pruning. All three trees are
given enough room to not interfere with each other.
            One of the biggest threats to espalier training (trellising) of fruit trees in our climate is sunburn from our intense sunlight and the number of cloud-free days. I have had problems with espalier trained fruit trees with direct southern or western exposure to the intense sunlight if not given some protection.

            Be careful with these types of exposures. It is important to provide enough canopy cover to reduce the sunlight on the load bearing branches (stems tied to the trellising) but still keep it restrained. In my opinion this must include the possibility of pruning during any month of the year.

Apple trellised about a foot AWAY from a century fence. It is NOT
trellised on the fence.
            Pruning during different months causes different results in the trees. Winter or dormant pruning is the most invigorating for trees while summer pruning (late March or early April removal of new growth) is the most devigorating.

            I would try to sites for ordering trees online; Bay Laurel Nursery and Grow Organic (which I think is Peaceful Valley but not sure) and yes with shipping is a similar price range.

            In past years Plant World has carried Dave Wilson trees but usually not until about April or so because a middleman must containerize/establish them since Dave Wilson only ships bare root trees.

Mushrooms or Space Alien Eggs?

Birdseye view of mushroom in the soil and opening
Q. Not sure if these are mushrooms or what they are. Was wondering if you could identify them. I have a small dog who will eat anything and I’m concerned they could harm her. They were found around several trees I hand planted. Just on the outer edge of the hole I planted them in.

A. The mushrooms are a type of fleshy puffball mushroom (inedible and perhaps poisonous) that grow underground off of rotting wood or even rotting woody roots and then open above ground to release their spores. They can spread but only if they have something to feed on underground such as rotting wood or roots.

I have received other pictures of the same type from other readers.



How to Keep Your Privets From Dropping Leaves in the Winter

Leaf loss on privets on left side of fence but not on right side.
Q. I have been living at my address for 7 years and the last two years my privets have turned brown and lost their leaves during the months of January and February. I attached some pictures.  Last year they came back although they weren’t as full and robust as they used to be. The Texas privets right next to them seem to do fine throughout the winter. Why are they all of the sudden loosing all of their leaves in the winter? What can I do to save my privets and have them come back with full growth? 

Leaf loss on privets on left side closerup
A. There are two things going on that need to be corrected or the others will start looking like the bad ones as well. You are looking at a snapshot in time. The two problems are how the plants are pruned and the depletion of the soil. I know that this is not very logical in relating why these plants are dropping their leaves but both are influential in helping plants keep their leaves during the winter months and does explain why they are less hardy than the others.

No leaf loss on Texas privet on right side of fence.
Most likely these plants are pruned with a hedge shears. And although they are being maintained as a hedge if we are not careful in a few years the old woody growth dominates the hedge (particularly at the bottom) and cannot support young succulent growth with lots of leaves. Hedges are supposed to be pruned like a trapezoid with the wider base at the bottom. Or they can be pruned individually to remove older growth (this is called renewal pruning) and then it can be hedged. This type of pruning causes newer growth at the bottom which supports leaves and then the plants are full from top to bottom.

The second problem is the type of mulch I think you are using. Rock mulch returns nothing to the soil. As plants grow and are pruned and the prunings taken away this takes alot from the soil. Simply applying a fertilizer is not adequate over time. The soil becomes depleted of the "organic matter" in the soil and many of the soil processes necessary for good plant health diminish over time to the point that the plant becomes "sick" or unhealthy. Unhealthy plants are more prone to winter damage than healthy plants. Healthy plants can withstand lower winter tempertures than "sick" plants. The first sign of low temperature damage of evergreens is the damage to leaves and stems and leaf and sometimes stem death and the leaves fall off.

To correct these problems you need to probably remove the rock mulch and put down first, compost and then follow it with coarse wood mulch that will not blow into your spa/pool. Bark is not suitable, it will not enrich the soil enough and will blow into the water. Coarse mulches such as you get from chipping trees interlocks and does not blow easily. Furthermore it breaks down and helps enrich the soil where bark does not. It is only decorative.

Unfortunately I think the damaged privets may be beyond help in the near future. It will take time for them to recover. If you want to invest that type of time then someone will need to start pruning them properly and renewing the soil with amendments that have been depleted. Otherwise I would just replace the plants as they go downhill and maintain a schedule of plant replacement over the years as the plants start to look ugly. Hope this helps.

Monday, February 11, 2013

Chums and Shothole Fungus

Q. I recently saw your youtube video regarding shot hole fungus and found it very helpful.  But I was wondering if you could provide some added insights.

Q. I live in zone 5B (Montreal, Quebec, Canada) and I planted a "chum" (cherry plum cross) tree a month ago in my backyard.  I believe it is stricken with shot hole fungus (see following video: http://www.youtube.com/watch?v=hs6jPVWP0-w&feature=youtu.be). As you said in your video I will only apply a Bordeaux Powder after the leaves fall in the autumn but I was wondering if there was anything that you recommended that I could do now to prevent the spread of the disease throughout my tree and prevent the fungus from spreading to my neighbouring fruit trees/plants (asian pear, european pear, raspberry, grapes, strawberries)? 

Should I remove and burn all foliage that is stricken with the fungus? No it's a mix of cherry and plum (prunus besseyi x prunus salicina). Perhaps it is a physiological disorder then.  I can remember we used to have a large tree that was planted in the same spot as my chum tree and it always prematurely lost it's leaves come late summer or early fall. Other trees all had their leaves but it lost it's leaves well before the other trees. In the end we removed the tree.  But I'm wondering if perhaps it is something that is in the soil.  I know the soil is quite tough in our backyard and is more of a clay soil.  Not sure if that provides any valuable insights.

A. You are out of my climate zone (and comfort zone) so I sent an email to Maxwell Norton, Fruit Advisor at University of California Extension in Merced, California and Tom Spellman at Dave Wilson wholesale fruit nursery for thier comments.
Most of what I understand is that plums seldom if ever get shothole disease. They get holes in their leaves but my understanding is this is physiological and not pathological in nature. Holes from shothole fungus should be rimmed with a purple or brown margin. When they occur physiologically then are not rimmed with any color but may have a crispy brown edge rather than any color.

Response From Maxwell:
Shot hole disease is rare on cherry and plum.  If it is warm enough and wet enough anything is possible. The non-infectious shot hole disorder on plum develops in late spring, beginning on older leaves and progressing out the shoot.  Small translucent spots turn brown and fall out. There is no treatment.
Sometime bacterial blast can cause holes on stone fruit.  Cold, wet conditions may favor it.

Prunus necrotic ring spot virus can leave cherry leaves tattered.  No treatment for that either.

From Tom Spellman:
Bob, Sprite and Delight (cherry plums) are superior selections of Myroblyn Plum that seem to fruit in all climates. The fruit is about the size of a quarter or slightly larger. They have fruited successfully in all zones from 3 to 9 and the fruit ripens July through September depending on how far north you are. They have a balance just slightly toward the acid side and are quite flavorful when tree ripe. They are interfruitful and will also pollinate with other Japanese Plums and Pluots. We offer them as single budded trees and also as a two in one with both varieties grafted to one  Citation rootstock.

The new release for the 2013 season is a true Plum X Cherry cross named "Pluerry - Sweet Treat". Don't yet have much information about zone adaptability but I'm hopeful its low chill as the fruit is delicious. In the central valley it fruits from mid July through August. Requires another Japanese Plum or Pluot for cross pollinization. I strongly feel Burgundy Plum and Flavor Grenade Pluot will work well.  We are releasing it as 500 chill hours recommended. However with the Plum parentage it could be much less. This is a great variety for experimentation.  I have recently planted two to my orchard and have it in a test plot in south Orange county.

Bob, I will get you a couple for you to try in the UNCE orchard in North Las Vegas.

Rolly Pollies Sound Cute But They Aren't!

Q. I was cleaning up my raised bed garden today, getting ready for spring planting, and I saw lots of worms. I know worms are good and I was happy to see them. But, I also saw A LOT of rollie pollies!  These were mostly under some newspapers that I had originally put down near the base of some plants as a mulch.  Are the rollie pollie beneficial to my garden or should I try to get rid of them?

A. Rolly-pollys are a real menace to things that we eat which are soft bodied. Particularly bothered are things like strawberries.

The roly pollies, sometimes we call them pillbugs or sowbugs, can be a very common pest of soft fruits and vegetables. These crustaceans (they are not insects but are more closely linked to lobsters) usually feed and abound in rotting or decaying plant matter which we usually call organic matter.

Stuff from plants which collects on the surface of the soil where it is wet will begin to decay. This decaying organic matter is a usual source of food for these common pests. They can be good guys since they feed on decaying plant matter and convert it to something that can be recycled and benefit the plants.

Once they get established however they can get a little overzealous and start to consume other plants or plant parts which are soft and succulent. Even new, small transplants! If strawberries come in contact with the soil surface where these creatures are feeding they don't distinguish between soft decaying organic matter and soft succulent strawberries.

So the control measures usually focus on keeping the strawberries from touching surface of the soil or decaying plant matter. This would require that the fruit be kept elevated off of the soil surface.

Other people may recommend using diatomaceous earth but I am not convinced that this will work with your roly pollies. It is better suited for very soft bodied pests which crawl along the surface of the soil.

These very sharp diatoms, at least this is the thought process, cuts or lacerates the pest and they succumb to the lacerations. You can also use traps in the beds and remove them from the traps as they accumulate.

This does not exterminate them but it does help to reduce their numbers and hopefully the damage from their numbers. These traps can be something that lies on top of the soil surface, just like you noticed with your newspaper, such as strips of carpet, cardboard or wood.

Removing these pests from these traps is simple. Since they like their social gatherings in darkness they tend to gather in these shady spots. Remove the shade and remove them by hand.

You can also put out semi rotten tomatoes or other vegetables which will act like magnets and attract these varmints. Then you can scoop up these rotting fruits and vegetables along with the pillbugs and dispose of them.  That won't get rid of them permanently but it will take the numbers down.

Saving Tomato Seed from an Exceptional Tomato Plant

Q. I planted a tomato last February. It is a Celebrity, the only one of 4 that survived blossom drop last spring. The plant started showing signs life in September so some extra watering perked it up, and produced flowers, many flowers. I covered it during our cold spell, and now continue to enjoy the last of the harvest even in January. One of those tomatoes will be my seed producer for future plantings. My dill was planted in September and still growing. Just about time to start planting again.

A. Great job keeping them going through the winter! You were fortunate to keep it alive. If this was a true Celebrity tomato, I believe it is an F1 hybrid released by Petoseed. It is a hybrid for sure.

This means that the seed from Celebrity tomato will not come true from seed. Seedlings from F1 hybrids begin "segregate out" from the parent plants used to make the hybrid. So don't expect it to produce the same type of tomato in the future by planting the seed it produced. Just a precaution for you to consider. F1 hybrids have to be purchased new each year.

F1 hybrid seed is made by cross pollinating two known and "pure" parent plants and saving the seed from this cross pollination. The seed that results from this cross is the F1, or first generation of the cross.

When F1 hybrids are created, plant breeders are looking for some specific advantage from the crossing of two different parent plants. In the case of Celebrity tomato it was predominantly for higher production and easier picking than either of its parents. It also has several resistances built into it including higher resistance to a virus disease, nematodes and some common tomato diseases.

To save seed from tomatoes and have the fruit "come true" and consistent, you should select what are called "open pollinated" types like, for instance, Brandywine tomato. Good luck and I hope you continue your great gardening experiences!

Lots of Plants Benefit from Iron Applications Now

Q. What other landscape shrubs benefit from an application of iron chelate? I know bottlebrush and photinia. Others?

Iron chlorosis on bottlebrush
A. That’s a good question. There are so many but for the most part those plants that originate from desert environments usually do not need it. Those that come from climates that are not a desert frequently will need it.

So for instance, Texas Ranger seldom if ever needs it. And likewise those that are sold as truly desert plants will not. There would be literally hundreds that we could list.

Iron chlorosis in photinia
There are some that are notorious for yellowing and needing iron particularly if they are put into rock-type desert landscapes. Just about all landscape plants in the rose family will require it including roses themselves and all fruit trees such as peach, plum, nectarine, pluots, apricots, apples, pears, etc.

Usually pomegranate and fig will not but I have seen pomegranate with yellowing and needing iron. Seldom do pine trees need it or most evergreens (keeping their leaves or needles through the winter).

As far as landscape trees go most like ash, mulberry, olive will not need an iron application. But a safe bet is if it is in the rose family it will probably need one.

Start Some Vegetables From Seed Now (February)!

All of the cold weather vegetables are still a safe bet such as spinach, peas, leaf lettuces and radishes. Vegetable seed have temperature germination requirements and it should be followed closely. I will post a chart on these temperatures on my blog.

If you plant vegetable seeds that require warmer soil temperatures there is a good chance that the seed will not germinate or it will succumb to disease problems such as damping off. Beans are a good example. If planted too early, they struggle and frequently die shortly after germination.

Don’t forget to start your warm season vegetables as transplants now. These are the tomatoes, eggplant and peppers. They need to go out in mid-March in warm locations. When growing seeds as transplants in the house you can do it in a bright window but you will have to keep the temperatures low or they will be weak and spindly.

Most warm season vegetables require warm soils for germination but can be moved to a cool location as soon as you see the first two leaves emerge.

Starting Tomatoes, Eggplant and Peppers UNDER Plastic

Q. What vegetables can we plant now in the garden?

A. If you want to try something unique try planting these warm season vegetables in small peat pots in a soil trench in the garden covered with plastic. Warm up the trench with plastic first before you put them in the trench. I will post some pictures.
Trenches made for tomato plants

Compost is added to the soil in the trench and mixed
Tomato seedling germinating in the trench under plastic and slit (not hole)
 is made to release heat

After March 15 or last danger of frost the lower leaves on the tomato plant
are removed, the soil in the trench is collapsed around the stem and a hole
cut in the plastic to allow the plant to emerge. I usually leave the plastic and mulch.