COLUMNIST: SCOTT GALLOWAY
Living in a Glasgow tenement, I feel your struggle. I have spent years building a collection of some of my favourite plants and due to the temporary nature of renting, I have never had an opportunity to actually plant them in the ground. This year though, I finally have a garden space I can use to grow, propagate, and enjoy my plants (with some caveats).
I have a good sized, shared tenement garden with a mix of grass, concrete paving, and shrubs which are maintained by a landscape gardening company on a bi-monthly basis. My landlord has told me I can keep plants outside but I cannot plant anything in the ground.
When the landscapers started working in the summer I had to find a way to grow around them, and with a few quibbles over weeds, and the ‘necessity’ of herbicide, I think we have found a way of working together.
To keep my plants out of the way of the landscapers, I was able to save some wooden palettes from my local coffee shop and use them on the grass to raise my plants off the ground. This keeps them out of hazard’s way when the landscaper comes round with his strimmer and knapsack sprayer.
It also encourages some of the ‘weeds’ in the grass to come through the palette that would otherwise be cut down in the maintenance regime, giving a small boost to biodiversity, particularly useful around the plants I am growing. I have seen several ladybirds and parasitoid wasps this summer that helped to keep the aphid population under control!
I keep everything I grow in pots but in the winter and spring of last year, I started repotting some of my trees and shrubs into air pots. These rather odd looking pots are excellent for encouraging fibrous root growth through a process called air pruning where the roots of the plant are naturally pruned through holes in perforated sidewalls. This enhances the overall quality of the root system by encouraging a healthy root mass to form, eliminating the problem of root circling that so often occurs in traditional container growing, while increasing oxygenation and nutrient uptake for the plant.
These revolutionary pots can be easily constructed and de-constructed with minimal damage to roots and come in a range of sizes perfect for when you need to repot.
I currently grow three different trees in these pots with great success so far. The highly attractive lacebark pine, Pinus bungeana, looks almost bonsai like in the one litre air pot but it is exceptionally slow growing, taking 50-70 years to develop its distinctive bark features, and I hope that by growing it in this pot I can help it develop a healthy root system before transplanting into the ground.
My Chinese lime and apple trees, Tilia endochrysea and Malus transitoria, are several years old now and really ought to be in the ground, but until I find somewhere permanent to plant them, I am going to keep repotting them in air pots, ensuring they have a well developed root mass.
Although these pots have revolutionised container growing, they are not recommended for growing herbaceous plants and are more suited to root development in trees and shrubs.
Although not necessarily an outdoor space, a tenement close can be a perfect environment for growing a range of interesting plants. Depending on the light levels and temperature, they can be an ideal space for trialling tender outdoor plants, such as exotic gingers, South African bulbs, and a range of succulents that all have high light requirements and need to be overwintered indoors.
Dahlias are also a great choice for container growing and if you can provide ventilation and keep them well watered and fed with a high potassium fertiliser through the growing season, you will be rewarded with dramatic blooms on your doorstep in late summer.
As many of these plants will not survive temperatures below freezing, it is a good idea to keep an eye on how low the temperature drops in your close. Even it drops below freezing, you can always wrap your containers in bubblewrap and mulch with straw or bark to protect your plants.
Container growing in rented accommodation is not always easy. It often requires a lot of work, from regular watering, to following a regular feeding regime, and checking pests and diseases on an almost daily basis (the blackfly aphid has been rampant this year!) The rewards, however, of growing in pots are abundant and offer us the opportunity to experiment with plants we might never be able to grow in the ground. So my advice is to try it, you really can grow anything, as long as you provide the right conditions for the plant.
Scott Galloway is a Glasgow based horticulturist and plantsman specialising in kitchen garden herbs, and the cross-cultural relationships people have with plants. Working with the National Trust for Scotland, he created a Scottish naturalised herb garden at Greenbank Garden, and is an RHS Plant Profile Writer.
Scott is building a National Collection of bergenia in conjunction with Plant Heritage and hopes to be an authoritative voice on the genus. Follow Scott on Instagram for more chat and watch his bergenia collection grow on @thebergenlist!