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'March' by Nicola Bush of the Roseland Nursery
 March! Probably my favourite month and when writing a column like this it is probably the one month when I will never be short of things to say or do.
Several years ago we made a propagating bench out of two old bunk beds. We put longer legs on, lined the bed bases with thick polythene sheet and covered with a 3’’ mix of sand and fine gravel. Then we laid on a soil warming cable and a further 2’’ of sand and gravel mix. The cable comes with full instructions and a thermostat so I can keep a temperature of 15-20deg C and raise seeds on an even and controllable temperature. It is also superb for bottom heat for cuttings and this month I shall take cuttings of pelargonium and marguerites. A propagator of any size is also useful for starting perennials from seed. Lupins, delphiniums, achillea, pinks and many others sown now may well flower this year.
Seed sowing indoors and out are the very obvious jobs for March and April and so I am going to look at a few jobs that may be overlooked this month in our enthusiasm for the new season.
- Split up polyanthus just after they have flowered. Just stick two hand forks into
 the clump and pull apart. Grow them on in a shady corner of the garden. They dislike hot summer sunshine.
- Prune any long shoots on camellias now if you want to tidy the shrub. Leave it too late after they have flowered and you will cut off next years buds.
- Split, plant or move snowdrops during their flowering or just after whilst there is still green foliage.
- Clip lightly over winter flowering heathers that are past their best. This keeps them compact and strong.
- Similarly with hebes, you can cut them back quite hard but I take about a third out each year to keep the size but to encourage new growth. If you want new hebes then take cuttings in August. The traditional varieties have become very difficult to obtain as so many growers up country have had mildew problems and they are now turning to New Zealand ‘wiri’ varieties. It is a shame as in coastal areas we do not have the same problems.
- If you have a large shrub to move then autumn is the time to do it. But if you dig a circular trench round it now and cut off the big roots it will form a dense tight root ball over this season making it easier to move in the autumn.
- I haven’t stopped mowing the lawn on and off all winter except when it was covered in snow or frost. Don’t be tempted to cut it too hard. Keep the cutters up high slowly lowering them each week or two. It may mean cutting more often but the grass will be happier for it.
- Be sure to harden off any veg plants before planting. If they are raised in a greenhouse they are still quite tender and need to be put outside during the day and even at night to acclimatise before exposing them to cold winds and cool soil.
- March is your very last chance to buy and plant bear rooted hedging or trees which are much cheaper than pot grown. The may need staking and will certainly need water whilst they establish.
- If you are unsure about seed sowing in the next few months, what to sow or plant and when, then just take time to go and look at the seeds on sale. The majority of veg and annuals that you want will have to be sown from now to June, even if they are winter veg. Read the packet front and see the sowing, planting out and harvest time and all will become clear!!
 With seed potatoes chitting and ready to go a recent customer started a great debate with me about blight in potatoes and tomatoes. The weather conditions have been perfect over the last three summers for this airborne nasty to proliferate. It really does appear overnight and it is devastating. I suggested planting new potatoes earlier in March so that one can harvest a bit earlier and even if blight does strike you still have a mature crop. (For tomatoes, shut your greenhouse at night and grow your potatoes as far away from the greenhouse as possible). The main question that arose from that was what about main crop? Well the answer is not so simple. The only choice is to buy ‘blight resistant’ varieties which are not always reliably so, or to spray against it which I would rather not do. The fact is that I do not grow main crop potatoes. They take up too much room and we have a great grower in Veryan at Churchtown farm and I go and buy a bag from him!!
Another question this month came from a lady who has discovered that the leaves on her citrus plants in the conservatory have rolled up and others have stuck together and the same has happened to plants in the greenhouse. This is the work of  the tortrix moth. If you unfurl the leaves or pull them apart you may either find great holes or a bright green caterpillar about half an inch long and a fine silk that has bound the leaves together. Squish it! They do form brown pupae that may be apparent on the soil or in the leaf. They often choose the new leaves on a plant and so can seriously harm the growth. The moth hides in corners and is quite small so difficult to find. I have been known to venture out to my tunnels with a torch at night to find it flying and now have a blue light positioned to catch it during the winter when the beneficial insects are less prolific. The tortrix moth seems to survive all weather conditions and can be seen outside doing its damage as the weather gets warmer.
What is the yellow mottling on my camellias?
This always looks a bit like a chlorotic problem which makes leaves, sometimes whole branches turn yellow or almost white. If a camellia is chlorotic and needing an acidic feed i.e. there is too much lime reaching it, then the whole bush will be affected. If it is odd leaves then it is more likely to be camellia yellow mottle and the plant loses vigour. The mottle is virus like and systemic within the plant. Do not use the plant for propagation and cut out all affected stems. It will recover.
Talking of recovery, the garden is emerging from this horrific winter and although many things are later than normal that should herald a colourful Easter.
'February' by Nicola Bush of the Roseland Nursery
 Bearing in mind the continuously cold weather and at the risk of boring the knowledgeable people amongst you, I am going to start covering some very basic concepts of gardening which are fundamental to understanding and practice and may stimulate the horticulturally challenged.
This month we will look at compost. No, not the stuff you make in your bin that is ‘composting’. What you produce there is a soil improver, because you cannot control its make up or nutrient value it is not suitable for raising seeds or plants. Composted garden material is almost 100% organic matter and is high in nitrates. As a soil improver it breaks open the soil, relieves compaction, increases drainage, assists nutrient retention and improves rooting. Its value is priceless but it is not a growing medium in its own right.
Compost is the stuff in brightly coloured plastic bags that greet you at the garden centre. Different sizes, different functions and a selection that bamboozles you when you just wanted to fill a few pots with plants. So which compost to buy and why? It depends on two things primarily. Firstly, for which plants you are choosing it and secondly what purpose do you wish it to fulfil? The packaging should give you that information.
Seed compost is very fine with the correct amounts of added nutrient for raising seeds but it is insufficient for a plant once it becomes a size for potting on. (Many of the multi purpose are now fine enough and strong enough not to bother with seed compost). At that stage multi- purposecompost can be used but as these are generally peat based they need to be monitored carefully or the plants can quickly become waterlogged or if too dry the medium is often difficult to re-wet. There is great debate about the continued extraction of peat and the decimation of the peat bogs and all sorts of alternatives are available and undergoing scientific and on the job testing. Many multi-purpose composts now incorporate well composted garden waste (from blue bag collections). Other medium available include coir compost from coconut husks but these of course have to travel many miles. Bark based composts are becoming my favourite as they are actually a combination of our garden wastes and forest floor detritus available in abundance in this country. These are carefully formulated by manufacturers with the absent nutrients added for general garden purpose.
As to the future of peat; well there is a lobby which says gardeners use so little of it in comparison with the power stations that it isn’t worth worrying about. But peat bogs only renew at a rate of 5mm per year so any saving has to be considered valuable, particularly as much of the peat now comes from Russia, so more air or sea miles to consider.
So whichever you choose, a compost labelled ‘multi purpose’ is good for potting on or for bedding out in pots for a season. If plants are left outside in it too long it will quickly become waterlogged and any nutrients will leach away quickly. Always buy it from a supplier that has kept it undercover as bags left outside in the open will be quickly leached of nutrient and be pretty much worthless to your plants. If the bag feels wet it will also be too heavy to carry safely.
Any of these multi purpose varieties will contain lime, so if you are looking to plant acid loving plants an ericaceous compost should be used. There is no lime in this compost and nutrients have been added for acid loving plants such as azaleas, camellias, rhododendrons etc. But beware, a multi purpose ericaceous will leach nutrients also and is for short lived usage as explained above.
 Now to the mysterious world of ‘John Innes’ compost. Mr Innes was a nineteenth century property and land dealer in the City of London. On his death in 1904 he bequeathed his fortune and estate to the improvement of horticulture by experiment and research. Directly he had nothing to do with compost, it was his money that enabled the research. Before the introduction of JI composts gardeners generally used a different compost for each species of plant. Usually the soil was not sterilised or heat pasteurised and so very often plants suffered from soil born insect and disease attack. The plant foods being added to the soil were unbalanced and so growth was variable in the extreme. In the 1930s two scientists at the John Innes Horticultural Institute, William Lawrence and John Newell, set out to formulate composts that would give consistently reliable results. After six years of experiment they determined the physical properties and nutrition necessary in composts to achieve optimum rates of plant growth and they developed methods of heat sterilising whilst not affecting the plant. These plant composts revolutionised the ways composts were produced and also the ways in which plants are grown in pots. Naturally the plant nutrients have been updated to gain the benefits of improving technology but the formulae were passed on to manufacturers (now the JI Manufacturers Association) and the Institute never sold or made money from actually producing the composts.
John Innes composts are soil based (not peat based) and the soil is carefully selected loam which is made up of sand, silt and clay (40-40-20) to which is added moss peat, coarse sand, grit and fertilisers. It is screened and sterilised and mixed in the appropriate proportions of the ingredients to achieve optimum air and water holding capacity and nutrient holding for different types of plants. Thus today one should think of John Innes as a formula, not a person.
The formula are mixed and numbered:
John Innes Seed Compost – for sowing almost any seed with nutrient for early development.
John Innes No 1 - for pricking out and potting on young plants.
John Innes No 2 – for general potting of house plants and plants in medium sized pots.
John Innes No 3 – a richer mixture for final planting in pots and generally used for larger specimens.
John Innes ericaceous - for lime haters and acid lovers.
The level of nutrient increases as the number goes up.
The fertilisers within we will examine at another time but these composts are a natural growing media for plants.
Humus and clay are a buffer to over or under feeding.
The combination of loam, peat and sand (rather than just peat in multi) provide a good balance between the amount of water held and the air capacity when the plant has drained.
The compost is easier to re-wet if it dries out.
Loam will retain higher levels of nutrient which would be dangerous in peat based composts
It lasts a lot longer than soil-less/peat based compost.
Finally, if January 2009 was the coldest for twenty years and January 2010 is vying for the record and February is still traditionally the coldest month, how low can it go? Got any echium still alive?
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'January', by Nicola Bush of the Roseland Nursery
 We will all have appreciated that many large private gardens developed in the mid to late 1800s by the grand Victorian gardeners were the product of the plant hunters who brought us so many species of plant indigenous to the Mediterranean, China and many parts of South America. The recent publicity about Trebah is a testament to the work of the Fox family who appreciated that they could grow so many so called exotic species within the fabulous garden valley.
What we have also come to discover of course is that those gardens were very labour intensive; no petrol powered lawn mowers, garden blowers or hedge trimmers. Just hard manual work by many men.
The first world war wreaked havoc for those gardens (never forgetting the men or their families). The labour force for the gardens disappeared off to war, so many of them never to return, and the priority was the war effort not the gardens, consequently many became overgrown and were lost. Hence the discovery of Heligan and Trebah and others in the next century.
Prior to the Great War many plants became very fashionable in Victorian days, not least the fern families. An enormous number were found and named and many were lost during the war but a handful of dedicated growers kept collections and their value for decoration in a damp area is unsurpassed.
 And not all ferns need a damp area. We see many of the asplenium growing in our dry stone walls, seeding and multiplying quickly and cultivated types selling for vast sums ‘up country’ whereas some of us may consider them as rather invasive. Similarly we can keep the dicksonias and washingtonias without fleecing in many parts and keeping their superb fronds through the winter.
Three years ago we had a very long hot summer and sales of exotics such as agave, cacti and succulents went thought the roof. Everybody shouted ‘global warming!’ and rushed to buy drought tolerant plants. In fact global warming almost certainly means windier weather and wetter weather with extremes of both and we have seen this to a certain extent over the past two years (let alone the past two months!!) So the succulents may not get too cold but they dislike wet feet all winter, but the ferns, herbaceous and evergreen prefer the wet and damp and many love our Cornish walls.
Now, the festive season is over, (yes it is), you have ordered your seeds and you are determined to turn the New Year with a fresh start in the garden.
Come on; get out of your chair and away from the fire. The days are short so make the most of the dry ones and start work now, and even though it’s frosty there is plenty of cold or slightly warmed greenhouse work to do. Its only 8-9 months until the local shows and you have to start thinking about it NOW!! If it remains so desperately cold though just put all the following jobs of for a week or so – this desperate cold will not last long – will it?
It is time to sow sweet peas in pots, in the greenhouse, if you didn’t do them in  November. Do not leave it any later; they will not flower as well. Give them a nice tall pot for that extra root length that they love. It is not too early either to sow those bedding plants that like a longer growing season. I start begonias into growth now so they are ready for bedding displays in May and will sow petunias, salvias and busy lizzies now too.
Just think of the money you will save rather than buying the plugs, and the satisfaction element is great. Sow in modules or seed trays. Modules are easier and cause less root disturbance on transplantation. Give them a cover of glass or cling film and newspaper if they need darkness and a little heat. Yes that all rolled off my pen easily didn’t it. Actually all you have to do is read the seed packet and do exactly as it says. Some seeds need light to germinate, some need dark and some need more heat than others. It isn’t rocket science, honestly, but most failures with seeds will be because of temperature or burying them too deeply.
More jobs for this month- but bear in mind the desperate cold and try and stay off frozen ground and lawns.
Sow broad beans now, they don’t need heat, but take precautions against mice. Broad bean seed comes high on their list of winter delicacies.
Take root cuttings from ceanothus, dicentra, echinacea, eryngium, oriental poppies and verbascum. Root cuttings from variegated plants will not show their variegation but will be green.
Check stakes and bindings on trees, high wind effect may cause movement or rubbing which fatally damages the bark.
Stay off lawns when frozen, but if we thaw out and if areas of the lawn are squelching underfoot take a tyned fork (hollow tynes actually remove a piece of lawn and leave better holes) and push in and wiggle to aerate. Hard work but pays dividends.
Back indoors in the greenhouse or on the window sill, sow small quantities of early lettuce ready to go out in February under cloches, also early cabbage and cauliflowers.
There are so many reasons to be so grateful we live in Cornwall, not least of which is that I may be stuck for something to write this month if I lived further north, those poor folks have to wait another month in their fireside chairs before they can do half of what we can in the garden and greenhouse! We may think its cold but it is nothing compared with some areas of the country.
Happy New Year to everybody! Get to it; I know Spring is round the corner, the daffodils told me…
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Click here to read Nicola's 2009 Gardening Matters articles
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