Washingtonia

[derrick]

My Washingtonia has started to grow again 2nd year in the ground .Looks better than last year had shelter over it on and off all winter i removed in feb It gets a little fungus on the leaves so shelter has to be removed in mild weather.Leaves are gone the same as last year .Another washy on my street looks good to has no damage but to close to house

[Dave Brown]

Have you just got the spears growing now Derrick

I know SteveW's was looking quite good without protection, considering the weather.

Mine lost most leaves, and those left had damage. Mine is growing in heavy Thames clay but I'm pouring 15ltr of 40C water onto the slate covering around it's base. The ground is covered in black weed fabric, topped off with clear plastic to kick start it. The warm water slowly soaks in and the soil temp at 30cm depth is nearly 5C higher than at this time last year. Was 10.7C April 15th 2010, 15.3C 15th April 2011. The result is good growth. Difficult to see exactly what is going on as need to be up a ladder, but 3 spears have opened in the last month and there is a conveyor belt of new spears coming along.

[Axel]

Have you just got the spears growing now Derrick

I know SteveW's was looking quite good without protection, considering the weather.

Mine lost most leaves, and those left had damage. Mine is growing in heavy Thames clay but I'm pouring 15ltr of 40C water onto the slate covering around it's base. The ground is covered in black weed fabric, topped off with clear plastic to kick start it. The warm water slowly soaks in and the soil temp at 30cm depth is nearly 5C higher than at this time last year. Was 10.7C April 15th 2010, 15.3C 15th April 2011. The result is good growth. Difficult to see exactly what is going on as need to be up a ladder, but 3 spears have opened in the last month and there is a conveyor belt of new spears coming along.

Dave, how are you measuring the beneficial effect of warm water? Last year you concluded the washy seemed to grow according to the mean airtemps and soiltemperature indeed did not match with the growthpattern. I have been pouring warm water for weeks on a Phoenix canariensis_CIDP and a large chamaerops now and i don't see any speeding up, even though the soil is soaked to 30C at times. It seems more complex to me than just warming the soil. I think the whole palm, from frond to growing point to trunk needs be at a certain airtemp before serious growth starts.

[Dave Brown]

Dave, how are you measuring the beneficial effect of warm water? Last year you concluded the washy seemed to grow according to the mean airtemps and soiltemperature indeed did not match with the growthpattern. I have been pouring warm water for weeks on a Phoenix canariensis_CIDP and a large chamaerops now and i don't see any speeding up, even though the soil is soaked to 30C at times. It seems more complex to me than just warming the soil. I think the whole palm, from frond to growing point to trunk needs be at a certain airtemp before serious growth starts.

Axel,
I know there will be far more factors than I as an amateur can measure,

for instance
average air temp,
max air temp,
min air temp,
soil temp 30cm,
soil temp 10cm,
soil temp surface,
solar heating of leaves and trunk,
rain
evaporation cooling
windchill effect cooling/heating,
humidity,
UV levels.
nutrient levels,
nutrient composition,
soil moisture

etc, etc.

What I can say is a combination of higher soil temp and high air temp gave more growth mm/day than high air temp with low soil temp. Heavy rain stopped it in it's tracks if cold and windy, even in May when soil temps were reasonable.

This April so far is as close to mimicing the late winter California climate as we can get.
Warmish sunny days with high UV due to our ozone hole, chiily nights, no rain. By improving the soil temp I am giving it the potential to do more when the other conditions are right.

The only way I can give it all the ideal conditions is to move it to a coastal position around 30/35 degrees north.

If you look at the climate of some parts of coastal California, it can be very hot 40C + with the wind off the deset, but also when the wind comes in off the cold Pacific current, summer temps can be as low as 18C by day and 10C by night. One thing that is uniform is that humidity is relatively low, to very low. This climate produces some wonderfully tolerant plants able to handle extreme heat, and cool conditions in the same season. All it asks is for no temps below -8C, no cold damp, and no long freezes

[Nathan]

My Washingtonia robusta has been visibly growing for several weeks now, I guess all the warm sunny weather of late has been to its liking

[derrick]

Yeh also had visibly movement for some time but had to be sure The 1st leaf is going to be part brown like last year it should grow out in time .Didnt think it would live it was a test Would like something bigger

[sanatic1234]

on both of my 1 yr olds they have gotten very small central spears and one looks pretty brown, they have been outside during the day so they are getting the air they need, should i increase the watering do you think? as they get watered once every week.

[Dave Brown]

They don't like being damp in the crown overwinter, but they don't like dry roots San. Even in their natural environment they have their roots in damp soil.

[sanatic1234]

It is a pretty hard one to judge really when they are potted aren't they, how would you suggest the best way of getting the watering right Dave?

[Dave Brown]

The old fashioned way of doing it was to let the top dry out for a couple of days then water again.but with peat based compost weight is the easiest way to tell, or use a moisture meter

[sanatic1234]

yeah i will give that a go then i will see if the soil is dry a inch or 2 down in the soil if so will water, i will pick up one of those moisture meters when im next in town.