"Chris Hogg" wrote in message
...
On Sun, 20 Sep 2015 17:43:25 +0100, Chris Hogg wrote:

On Sun, 20 Sep 2015 17:54:41 +0100, "Frank Booth"
wrote:

I have a couple of these plants in 2 separate areas. Overall they seem
to be
doing ok and growing well. But I've noticed that when they put on new
foliage in early spring and now sometimes the new foliage starts yellow
in
colour, although it tends to green up later. Is this common?

https://www.flickr.com/photos/12074760@N03/21569825095/

Used to be known as Lithospermum. I assume yours is 'Heavenly Blue';
that's the popular one. Not sure about the yellow growth. IIRC it
likes an acid soil, so perhaps yours has a touch of chlorosis. What's
the pH of your soil? Try giving it a shot of Sequestrine.
http://tinyurl.com/qxb652n

Pah! I've just looked it up on the RHS web site. It says that
Lithodora diffusa is suitable for chalky soils! See
http://tinyurl.com/oaz9og4 and scroll down to Alpines. Yet the RHS
encyclo says Lithodora diffusa needs an acid soil (although it also
says most other lithodora species like an alkaline soil). That's
hardly consistent advice, and from the RHS too! So what to believe?

Nitrogen deficiency can also cause chlorosis. Back it both ways: feed
with a fertiliser designed for ericaceous plants that contains both
nitrogen and sequestered iron, such as Miracle-gro Ericaceous plant
food http://tinyurl.com/pga5akj .

I would certainly say that Lithodora has ericaceous requirements. That seems
to be the consistent message from what I've read on different sites. What
seems to happen in my case is that a small part of the plant develops yellow
leaves to start with, but during the growing season the plant becomes all
green. I have added sulphur powder each year in spring to the soil, but it
seems to have little effect. If the pH of the soil was too high I'd expect
all the leaves to turn yellow, but as you can see from my photo it's just a
few.

Curiously, last year I took a cutting in autumn and stuck it into the
ground elsewhere. The leaves soon turned a sickly yellow and I thought the
plant would soon give up. But come spring the cutting revived and 6 months
on it's now made considerable growth and is a healthy green colour...which
brings me back to the query of whether it has a natural habit of producing a
few chlorotic looking leaves when it first starts to grow or is it an actual
deficiency?