Preparing soil for lavender

Hi All,
I planted a lavender hedge a couple of years ago in front of a west facing bay window that gets a lot of direct sunlight after about 10 or 11 am. We had our driveway done and the builders created a trench in front of the bay so I could plant something. At the time the trench (I think) was just filled with cheap compost from b&q. Anyway I planted this lavender and for the last 2 springs it has bushed out very nicely but never really flowered very well. Now (July) it is practically all brown, twiggy, with only a few green leaves at the ends which are also going brown - it looks terrible!! I suspect that the drainage isn't good enough and the roots are rooting. My plan is to dig them up to look and then remove all the soil and replace it.

So my questions are:
1. Knowing that lavender like poor soils and good drainage I was going to remove all the soil from the trench down to the sub-base (about 12 inches probably). Put a couple of inches of large gravel at the base and then a 1:1:1 mix of horticultural-grit:sand:compost. Would that work ok?

2. I've seen some amazing lavenders in the area - bushy with hundreds of large purple flower stalks. Could you recommend me a nice bushy variety!?

3. I'm assuming this is a drainage problem - could it be something else?!

Thanks and sorry for the long winded post!!

Matt


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Oh yes one other thing! Would now be a good time to plant some new ones or should I wait till next spring?

Thanks!


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IMHO water needs to drain away, just putting grit/stone in the bottom of a trench just gives water somewhere to sit ... I would want to put a small-bore (2" say) perforated drainage pipe in the bottom of the trench, with gravel, and ideally route that to somewhere the water can flow to, failing that a soakaway

If you planted it Multi-Purpose Compost (MPC)? it will have run out of nutrients, and it will also have compacted (which will have compounded the drainage issues). A soil-based compost would be better. The mega-wet winter (assuming you had that too?) would have exacerbated the problem hugely.

It should have flowered "some-what" in Year 1 and "well" in year two, so soil-quality and/or drainage and possible nutrients could be the problem for that as well as the distressed foliage. Lavender likes a poor soil ... but not one that is delete of nutrients!

I suspect that the problem is that the "soil" is not free draining enough. If you remember what the "cheap compost from b&q" was that would help - MPC??

Hidcote But buy them from a specialist nursery, which say that they grow from cuttings and NOT from seed, as the cheap versions will be from seed and will not be the same powerful colour - seed-grown is also liable to being variable size as well as colour.

Yup. Young Lavender plants may over-winter badly, more especially in their first year, so best to plant them in early Summer (rather than late Spring) as with the heat they should then make a flying start and be well established by the following winter.

If you have a cold greenhouse / conservatory (i.e. unheated) you could buy them now, pot on during the summer (probably as far as 1L pots) and over winter them almost dry, and then they will be bigger plants next year than you would have bought. Typically Lavender is delivered in 9cm pots and they are quite tidily to be planting out (by comparison a 1L pot is about 15cm)

I got mine from Downderry Nursery, but there are several other specialist nurseries
http://www.downderry-nursery.co.uk/plant-details2/?plant=251

 

Hi Kristen! Thanks for the brilliant reply!! I can't remember exactly what they filled the hole with - they may have transplanted some of the soil from a different area that they had dug up - we have very clay soil here (South Wales). I did add a bag of grit to the soil at planting time and tried to mix it in but all very half heartedly and I can remember thinking that I needed to add more but didn't!! They seemed to grow very vigorously this spring and I was relieved because yes we had had a very wet winter - lovely and bushy and green and then the flower stalks appeared but the bloom was very disappointing. Some of the lavenders in the area look absolutely stunning (but not mine!!)

I've taken some pictures of them now so you can see what I mean - I'm really disappointed!!



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I did by them from a nursery online and planted them I think in early September 2012. They said it would be ok and I just wanted to get them in the ground! Last years bloom was only just about OK. This year as you can see its hopeless!!



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I don't think it is related, but it won't have helped, but looks like you haven't pruned them after flowering in previous years?

Getting to grips with pruning them is critical. You need to stop them getting straggly and with lots of old wood. You need to cut hard back after flowering, without actually going into old wood - so do not cut back more than the lowest leaves that are alive and healthy. Best to look on the specialist Lavender websites for a decent description - they'll describe it better than me, and probably have videos too

 

Hi Kristen,
Would you say its worth me replacing them? It's not an option to install drainage/soakaway but the trench itself is quite deep so my idea was to put a few inches of large stones at the base almost to act like a sump which will slowly drain away but still keeping the roots dry and then filling it with amended soil. I found a Monty Don video where he recommends 1:1 grit:compost for cuttings, so do you think 1:1 grit:John innes no:3 might work or am I just wasting my time? On the subject of pruning I thought about it last September(ish) but remember seeing there wasn't much greenery before the wood started so didn't (as I didn't want to cut into bare wood!)
Thanks again!

Oh yes one other thing!! Do you think its worth trying to salvage my existing plants?!

Thanks,
Matt


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Difficult to say, because I am not sure that the drainage is right. Something has upset them! and I am guessing you had a mega-wet-winter like we did. A more free-draining compost would undoubted help, but I'm not sure it would be enough. But having said that, if you are minded to have another go then best-foot-forwards and fingers-crossed!

I think that would be a good medium. Perhaps even JI#2 (less fertiliser) & grit. (Best to use horticultural grit, rather than regular "gravel"). Would it be expensive for the area you have?

Sadly not. They needed pruning last year, and are now rather leggy. They might be able to be pruned into recovery, but that process is tricky and not guaranteed to work. You could try taking cuttings from them, to save the cost of new plants, but I very much doubt that they would be big enough to plant out next year, so that would be a two-year project.

I agree with your plan of digging out, adding drainage stones, and then free draining "soil", but I'm just not sure if excess rain water CAN soak away from that bed well enough t prevent eh plants from getting waterlogged - which Lavender will hate. Having said that, if they are currently in B&Q Multi Purpose Compost that alone might be 90% of the problem (combined with a wet winter), so there might well be hope

 

As the original plants obviously grew well enough to fill the`space the conditions can't be that bad. I agree with the pruning though, I think this may be just too much old wood. I'd start again but it does look as though it's worth a go. There are nice quality plants in 1ltr pots in my Morrisons for £2 at the moment. Why not just replace a few of your plants for now so that you can see how they go before deciding about the whole bed.