Question
QUESTION: Hi Steve,
I need to buy some orchid bark to repot my Cobra lillys but Im un sure whether coarse / medium or fine bark is best for them?
Could you advise please?
I live in Lancashire,North West England and it seldom gets very hot.

Regards
Rob

ANSWER: Darlingtonia californica ("Cobra Lily") roots are fairly thin, so I would personally use the "fine" grade of orchid bark, but I don't think I would use it alone. Instead I would make a mix of orchid bark, perlite, sphagnum peat moss and silica sand, or I would make a mix that has no orchid bark in it at all.

However, I would like to refer you to the expert Sarracenia Northwest (Jeff Dallas and Jacob Farin), who I'm sure have more experience than I do with this particular carnivorous plant and growing mixes that it may tolerate or prefer. If you ask this same question of them, you may get a more detailed answer.

Best wishes,
Steve

---------- FOLLOW-UP ----------

QUESTION: Hi Steve,
Thank you very much for helping me.I should have made clear that I intended to use a 1;1;1 mix of moss peat and perlite with the bark (Iv got Adrian Slacks Carnivorous plants book).I`m going to go with your suggestion of `fine`grade material.Once again,I really appreciate your (quick) help - and I`m certain my Darlingtonias will too!.  Regards  Rob

Answer
Hello Rob--

If you're going to use a 1:1:1 ratio of sphagnum peat moss, perlite and orchid bark, then you could probably use the medium orchid bark instead of the fine if you would like. Either grade of bark would probably work well. The main use in this type of mix of the perlite and bark is to displace a portion of the very water retentive peat moss, which means that the mix will dry out much faster. This is advantageous to Darlingtonia which seem to like or need plenty of air around the roots. Even though in their natural habitat they are often standing in water or in very wet conditions, it is usually moving water (although sometimes fairly slow moving), naturally aerated and fresh, not stagnant.

So in cultivation, in order to get the air in the mix, it is helpful to make a looser, less dense growing medium that drains and dries more freely. This means however that one must water Darlingtonia more frequently. A 1:1:1 mix with only one major water retentive ingredient (the peat moss), is 2/3 by volume non-water holding material (or rather, material that holds very little water), so it will dry more quickly than the typical 1:1 mix suggested for Venus Flytraps and other plants, composed of peat moss with either orchid bark, perlite or silica sand.

I would still like to refer you to the expert "Sarracenia Northwest." Jeff Dallas and Jacob Farin of Sarracenia Northwest live near Darlingtonia and specialize in American pitcher plants. They may be able to offer some very good comments and advice.

It's a pleasure to know that American pitcher plants are being enjoyed by growers such as yourself in the UK and around the world. Thank you for your interest in these great plants, and for your question.

Best wishes,
Steve