BonsaiNurseryman

Automatic Watering Timers and Valves

(This post first appeared on BonsaiTALK on 6/26/06)

I have installed and used many systems over the last 25 years or so, and one thing I can tell you is that no system is 100% completely foolproof. However, there are ways to get the failure rate very low. First, any battery operated timer is a crap shoot. You might get the best performance from the cheapest on the market and the worst from the most expensive, or have nine of the same brand work in bulletproof fashion and the tenth DOA, or nine DOA and the tenth work forever. Constant vigilance is the only thing that is going to save you with battery operated systems. If you use one, have someone make sure it came on each day...forever.

By far, the most reliable system is a hardwired 24V timer run with a 110V transformer backed up with a 9V battery. If the power fails, then the backup battery saves the program, but won't operate the system. When the power comes back on, the program will work again at the next cycle, or a cycle will complete if the power fails in mid cycle. Replace the 9V backup battery once a year. Even if the 9V dies and the timer loses its program, the system resets to come on every day for every zone for 5 minutes, so everything gets some water and you know something is wrong. The timer powers a 24V electric valve (antisyphon or straight thru) which are quite inexpensive, $10 to $15 each at big box stores. These valves can fail too, but if they work coming out of the box, they usually work for decades. They are not designed for very low flow, so if you use them for drip systems, you have to have enough emitters to make sure that the flow is high enough for the closing actuator to function (it uses the pressure differential to pump up a diaphragm). Usually a flow rate of over 1 or 2 gallons per minute is adequate. If the valve takes a very long time to turn off, you have a problem. Also, it's a very good idea to put a filter BEFORE the valve, since tiny sand particles have a way getting in the wrong place and jamming the small piston in the solenoid, or blocking the orifice.

I have about half a dozen 6 station digital Lawn Genie timers that are nearly twenty years old and still functioning. Most of my electric valves are less than 15 years old since I switched to 1 inch valves about that time, but about 90% of those are still working. The solenoids and the diaphragms are replaceable on the Lawn Genie types (that company has been bought several times over, so I don't know what the current brand name is, but they are the ubiquitous blue green plastic valves). So you can keep these going nearly forever if they don't freeze and crack the valve body.

The timer should be housed in a dry indoor location if possible such as your house, basement, garage, or permanent type shed. You can run the control wires anywhere to actuate the valves, which is a wonderful advantage over hose end timers. Common 18 or 22 gauge thermostat wire works just fine, and if buried, doesn't even need conduit, unless it is in an area where you dig a lot and are likely to cut it. Above ground it should be in conduit or out of the sunlight which will degrade the insulation over the years. Wire connections can be made with simple plastic wire nuts. I put a squirt of silicone rubber in the wire nut before twisting it on to make a simple effective watertight connection.

It's definitely more work to install a permanent system, but not all that more expensive. In the long run, it is considerably LESS expensive. You only have to go through two or three hose end timers to pay for permanent system. In addition, you have a LOT more capacity. A six station timer would allow you run all your landscape watering needs and your bonsai.

Brent

Spring Freeze Damage

Late spring freeze damage is a common problem that often goes undiagnosed.  I see this a lot, too much actually, at our new location which suffers every year from late spring freezes. It's not the minimum low winter temperature that's the problem, it's the early warm spells that bring plants out of dormancy prematurely. They don't even have to bud out. A few days to a week of warm weather is enough to get the plant active and lose most of its cold resistance. Then, even a moderate freeze can severely damage the tree, all without you ever seeing a bit of green.

This past spring was one of the mildest on record for us because of our almost continual cloud cover and rain. The vineyards around here didn't have a single frost day (where they turn on the irrigation to protect the vines), the average is 20! Despite this, our peach tree was severely damaged and nearly died. I saw it coming. The buds started to swell way too early and some flowers even opened, but then we had a freeze of about 25F. The flowering stopped and it appeared normal for several weeks. But as other plants began moving out of dormancy normally, the bark turned black on most areas of the peach tree and the freeze damage was evident. Other Prunus, even one that was only about 50 feet away was completely untouched because it flowers later and stays dormant longer.

I have also witnessed this on my Chinese elms, Ulmus parvifolia cvs, and have seen first hand the differences between the cultivars, some hit hard by late freeze, others untouched. When this happens, the bark turns darkish, buds are all dead from freezing, but the cambium is still alive. Roots can also be damaged, both by the freeze and the lack of any response from the upper parts of the plant. In severe cases where the upper portion of the tree dies, but there is little or no root damage, suckering may occur. If there is less damage, only parts of the tree are killed and the more protected, usually inner and lower branches, survive. Even though the cambium will remain green for a long time, there are no live buds present to open. Under some rare instances, where damage is just enough to kill buds, but not cause other cellular damage, deeply buried dormant buds may break.

Other species that suffer from this problem are Acer palmatum, A. buergerianum (especially young ones), most Prunus species, many Ulmus species, Liquidambar orientalis (suffers from early fall freezes too, same symptoms), Morus, Wisteria, Carpinus coreana, and many Mediterranean climate species. I have witnessed the problem firsthand on all of these.

You Can't Win 'Em All

This is a difficult post to write and I have been avoiding it for several weeks. I hate to admit that I am beaten, so let's just say that I am refusing to fight any longer. I am going to discontinue Prunus mume and most other Prunus species from the inventory. I know there are dozens of you on the waiting lists anxiously awaiting the availability of the various cultivars, but it just isn't going to happen.

The new growing grounds just isn't a suitable environment for mume. Uncertain spring weather, late spring freezes, and the resultant fungal attacks just devastate the plants. I can protect most of the cuttings, but without stock plants, I can't grow enough wood to make the cuttings. Last winter, even the rooted cuttings I did manage to grow were totally wiped out by voles, along with the 'Evergreen's Roughbark' trident cuttings. It is very discouraging to say the least. I was prepared to make one more shot at it this year, but about three weeks one of my 'Peggy Clarke' mume stock plants started to decline. It's now dead. This is a ten inch caliper trunk tree that I have been growing for over fifteen years. I had hoped one day to make an enormous and spectacular bonsai from it. No more. That really took the wind out of my sails. I now only have one large 'Peggy Clarke' and one large 'Bonita' mume left. All of the 'Matsubara' stock plants have succumbed. The 'WB Clarke' and 'Rosemary Clarke' stock plants are also dead. Most of the purple plums are also dead. I can't see any point in going on.

So, that was the last straw. I will be contacting the waiting list customers soon with this sad message, and I apologize for getting your hopes up, but I can't do the impossible. If there is some enterprising nurseryman out there in a mild climate, cutting grown mume is a nice niche market for you, both for the bonsai and landscape market.

The good news is that the pine grafts are beautiful. I have my fingers crossed, but it looks like there is going to be a bumper crop of Japanese Black pine cultivars ready this fall as two year old grafts in one gallon pots. We should be able to satisfy the waiting list and then some. Right now it looks like these Pinus thunbergii cultivars will be available:

'Akame'
'Banshoho'
'Brocade'
'Fuji'
'Hachi Gen' (cuttings)
'Hayabusa'
'Katsuga'
'Kyoko'
'Nishiki Tsukasa'
'Thunderhead'
'Yatsubusa'

A couple others may also be ready depending on how much growth there is between now and Sept. A few Japanese white pine cultivars may also be available by then, but since these are slower growing than the black pines, it may take another year for most of them. But looking good right now are these Pinus parviflora cvs:

'Adcock's Dwarf'
'Ara Kawa'
'Hagarumo'
'Ibo Can'
'Kotohime'

One other benefit of putting the mume behind me is that I can again concentrate on propagating Japanese maple cultivars from cuttings. I really haven't been doing any of these since moving to Lake County, but I think I have solved the cultural problems  now, and my stock plants are beginning to flourish. I should be able to get sufficient wood to do some experimental batches this month. I just finished installing the cooling system for the propagation greenhouse this week, so now it is completely climate controlled, and should be suitable for these very touchy cuttings. The Acer palmatum 'Kiyohime' and 'Yuri Hime' cutting grown plants I had in one gallon size were a really big hit and sold out very quickly, so I am anxious to get some more started. By this fall or next year, I hope to have 'Ao Kanzashi' cutting grown plants ready in one gallons. This is an excellent, but somewhat rare cultivar with small pale green leaves that are more incised than the species. The leaf reduction and ramification is remarkable, but it is a relatively fast grower.

And, yet another coup, I have found someone to graft Cedrus libani 'Green Prince' for me. The first crop is expected any day now. They will have to be repotted into one gallons this winter, but hopefully will be ready by Sept 2007. Some folks have been waiting a long time for these, as well as....wait for it...Contorted Catlin elms. Yes, the first batch of decent cuttings of Ulmus parvifolia 'Contorted Catlin' are now in 2 3/4 inch pots growing in a climate controlled house to push their growth to the max. I have about forty of them now, so keep your fingers crossed. They will still be small, and they won't be cheap, but I should be able to knock the waiting list down substantially. These have been unbelievably difficult for an elm!

On a happier note, Dr Bob, my apprentice now has babies! Twin girls born June 7. Congratulations Bob and Patricia. I am sure you will see announcements, details and pictures soon at his blog and in the forums.