It's not drought, it's Denver!

I was lucky enough to be in Denver last weekend - my first time in the state of Colorado. As ever when I travel, I seek out a garden or two to visit and a quick search on Google revealed the Denver Botanic Gardens to be only a mile or two from where we were staying downtown.

I was particularly interested to see the water-smart garden within the 23 acres of planting. Denver is known as the the 'Mile High City' and the air is pretty dry at that altitude. Added to that, the location of the state within the US – it's about as central as you can get, so moisture in the air will have been shed long before any weather front reaches here. As a result, this should be the perfect place to learn about gardening with limited water.

This particular area was situated in full midday sun and filled with plants typical of dry semi-arid regions with all the adaptations you might expect to ensure the plants' survival. The sloping border is watered only seven times during the summer season and plants are grouped together according to their water requirements. Thirstier plants are positioned at the bottom of the border to maximise their use of run-off or gravitational water.

Sedums were well represented - the photo below shows Sedum 'Purple Emperor'. Thick succulent leaves allow the plant to store excess water for use later.

Lavenders and Lamb's ears (Stachys byzantia) were also included in this garden. The former has reduced leaves and the latter has fine hairs covering the leaf surface. These characteristics serve to reduce water loss by transpiration. Both plants have a silvery colouring which acts as a reflector to the strong rays of the sun.

Agave, cacti, yucca, eucalyptus, oaks and cypress line the back wall of the border and create focal points in the central areas.
The photo below shows Texas sotol (Dasylirion texanum), a relative of yucca. Its distinctive flower spike appears from May onwards and grows to an impressive 15 feet in height - and is apparently adored by hummingbirds!

Many of the smaller plants featured along the front of the border such as salvias, alliums and fine grasses are those or close relatives of those that would be easily found in UK nurseries and garden centres. Maybe, if the drought conditions continue on our side of the Atlantic, we'll be taking the lead from here and planning our own future garden plantings in terms of low water requirements and heat tolerance.

The promise of things to come

March is definitely one of my favourite gardening months. Not only do the days visibly get longer (remember just a few weeks ago when it was dark at 5pm?) but the garden is positively burgeoning with the potential of what the year will bring. 

The Conference pear tree, despite a severe pruning in November, looks to be promising a good harvest for 2012. This one is a small specimen tree that I hemmed in quite tightly with two raised beds back in 2009. Thankfully it doesn't seem to be holding that against me and is a regular and prolific producer of lovely big juicy pears that are perfect for my tarte tatin recipe.

Bursting into leaf already is a lovely Hydrangea anomala subsp petiolaris - the climbing hydrangea. Situated on the north facing fence, it grows incredibly well and produces huge attractive flowerheads each year. Even during the winter when all the laves have fallen, this plant manages to look appealing with its red/brown peeling bark and framework of stems. Last spring it took a bit of a battering when the chickens took a fancy to the leaves and totally stripped the lower third - basically to the height that they could jump...

The old March favourite - Forsythia x intermedia - is just coming into its sunny yellow best. This much maligned spring-flowering shrub is harshly judged by many for being brash and ubiquitous, but I think they're two of its best features. These shrubs add such an injection of vibrancy into the garden at a time when signs of life are much needed. Bring it on, I say.
My forsythia is a fairly old specimen judging by the thick woody basal stems. In June last year I embarked on a rejuvenation pruning plan - the eventual aim being to remove most of the thick old stems as far down as possible to encourage new flower carrying growth. As advised in many books, I'm doing it over a three year period - one third of old stems being removed each year.

And lastly, the ornamental quince (Chaenomoles spp, possibly japonica) that seems to be throwing up more and more suckers every year. It blossomed in early Feb and was then hit by the snow and below-freezing temps. But since then it's rallied with even more blossoms - in a gorgeous rich shade of red - quickly followed by small shiny leaves. I usually get between 2 and 4 small fruit from this most years, which I tend to chop small and add to any jam I happen to be making. Judging by the  number of flowers on it, maybe I'll have enough for a small pot of quince jam this year.

BTW: for those who have noticed the time of this post - I'm not suffering with insomnia, I'm just in a different time zone currently...

Hard graft

The last few college days have involved rather a lot of practical work. We've been out in the polytunnel or on the plots doing everything from sowing seeds and collecting propagation material, to planting trees and creating raised beds. (The latter two requiring more bending and spade work than my back was really comfortable with.) But I was very enthusiastic when we got on to grafting fruit trees. The particular form of grafting we carried out is called 'whip and tongue grafting' and refers to the specific angled cuts that need to be made in both the rootstock and scion to ensure that there is good contact of the cambium (the growth tissue) between the two. The technique is described on the RHS website here. Armed with my brand new grafting knife, I set about practising ahead of the timed assessment.

practice graft in the polytunnel using a grafting block

Once I'd got the hang of the intricacies of the cuts, the practice grafts were relatively easy as they're done at bench height using offcuts from apple trees pushed into a grafting block to simulate the rootstock. It is quite a delicate operation though because the most natural way of holding each 'twig' while you're cutting it always seem to be with your non-cutting hand in direct firing line of the blade should it slip... 

And later it was time for the assessment, where we had to complete 3 grafts onto planted rootstock in 20 minutes. Being at ground level is a bit more difficult than bench level - you can either bend right over to work close to the ground (not great once you're over 35, to be honest) or kneel on a grafting block (a bit tough on the knees but bearable for 5 mins at a time). We each had a line of 3 rootstocks and a choice of scion - I decided on Blenheim Orange. I finished my grafts well within the 20 minutes, fully labelled and trimmed to an appropriate height. Suburban Orchard here we come!

My three grafts in line, front to back. 

The salad challenge

I'd fully intended joining the 52 week salad challenge that was started over on VP's Veg Plotting blog back in January. I even thought I had a head start as I'd managed to germinate a few lettuce seeds (butterhead type) in the greenhouse in December. Smugly I transplanted the strongest 2 to small pots and waited for them to burst into growth so I could have my first salad by the end of January.

note: reused label, thus date from last summer

And I waited, and I waited and then I waited some more. And then I realised that small pots of my own homemade compost might not contain the optimum nutrition required by these young plants. (Note to self: pay more attention in plant health and nutrition classes...)

As the weather had recently improved, I decided the time was right to send these little seedlings out into the big bad world to fend for themselves. So I planted them out into my salady/green leaves raised bed and topped them off with a cloche (yes, another one - I couldn't resist it/it was in the sale/I had a 20% discount code). It's a beautiful replica Victorian one and the lettuces seem to really be enjoying themselves in there...

In the spaces around them I have sown some mixed salad leaf seeds that have performed very well for me in previous years - a mix of oak leaf, cos and something resembling mizuna.

Meanwhile back in the greenhouse is a rather large tray of lettuce seedlings that I brought home from college last week. We're doing lots of practical sessions at the moment and did our 'seed sowing in containers' practice last month - of which this is my result. A conservative estimate puts around 200 seedlings in this tray - and they're still germinating. Maybe this year is my foray into commercial lettuce production?

seedlings as far as the eye can see...

Wildflowers count

There has been a lot of UK press about wildflowers recently. From Sarah Raven to the RHS, everyone who is anyone in gardening is planting or sowing wildflowers to help our pollinators in need. I've got lots of california poppy seeds sown in gravel along the alleyway at the side of my house that usually attracts a plethora of buzzing insects. Hopefully any of you who have the space will be making their own contribution, but even if you don't have any space, you could contribute to the knowledge of our current wildflower status by signing up for the Wildflower Count organised by Plantlife each year. On signing up (don't worry, it doesn't cost you anything) you'll be allocated an Ordnance Survey grid square selected for proximity to your postcode. Then, armed with their handy photo guide, you simply go for a 1km stroll across that square, identifying any of the 99 listed most common UK wild flower plants. It's pretty easy, could get you (and your kids) exploring a part of your town/village/city that you've not really seen before and the data all goes towards a better understanding of the status and spread of our native flora. Spread the word - they're looking to increase their registered surveyors in 2012.

The website for signing up is here. Go on - count a cowslip today!

(image from Wikipedia - released to the public domain by the originator)

Early season seedlings

On the first day of March, a little bit of a round up of what's germinating so far:

early toms and chillies - one or two of each of the tomato varieties have germinated but there's been a distinct lack of chilli action so far. Chillies require a temperature of at least 18-20 degrees for germination so perhaps they weren't kept warm enough. So, I have sown a few more pots of those, and of some other chillies (I seem to be growing 9 varieties this year...) and they're all staying in a propagator on the hot water tank until signs of life appear.

leeks - these took a few weeks, but have now started to push through the compost surface.

nasturtiums - I grow these because they're a) easy to grow, b) pretty and colourful, and c) keep blackfly off my broad beans. These germinate amazingly quickly and are already potted on in the greenhouse. I plant them in the raised beds where the broad beans go and they seem to thrive. They're also really easy to pull out or move if they start to become a bit dominant.

I've now started to chit some parsnip seeds on a piece of damp kitchen paper. These were self-saved in 2011 (see post here), so I'm really curious so see what the viability is like. As the seeds germinate and develop their primary root (the radicle for the gardening nerds amongst us), I'll transfer them outside into their growing position. You need to do this quite quickly, otherwise the tiny root begins to grow into the kitchen paper and you could damage it upon removal.