Architectural Plants. Christine Shaw

hand – no roots left at all! By scraping around under the soil, large fat white grubs can be found (they’re large and fat because they have been gorging on the entire root system). Other signs to watch out for are nibbled notched leaves, which are made by the adult form of this nocturnal creature.

      Once found, dispose of the entire contents of the pot, fill it with fresh compost and start again. There are some exceptionally nasty chemicals around that can be added to the soil to ward off vine weevil, but using a loam-based compost and giving an occasional dose of a natural predator (a nematode worm that eats only the bad guys) works very well. Vine weevils are lazy things and prefer to burrow through soft, peaty compost rather than heavier loam.

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      Echeveria glauca is a favourite snack for vine weevils.

       Overwintering

      No plant will stand having its roots frozen solid for weeks at a time. If you have a nice little courtyard garden in a warm inner city or if you live in a mild area near the sea, then this won’t be a problem. In colder areas, pots may have to be moved indoors or wrapped up. Choosing very hardy plants is obviously sensible, but the roots would still remain vulnerable. If cold winters are a regular occurrence in your part of the world, before planting, line the inside of each pot (excluding the bottom) with a thick layer of bubble wrap. This is completely invisible once the pot is planted up and much more pleasing to the eye than an old blanket wrapped around the outside of the pot.

      Moving a heavy pot that has been planted up to less cold conditions indoors can be rather a nuisance. There are various trolleys and sack barrows on the market, but the best one I’ve come across has a beautifully angled shape and heavy-duty pneumatic tyres, which make light work of the whole procedure.

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      Canna indica can easily be overwintered under glass if it is planted in a container.

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      Aspidistra elatior is a nice leafy choice for a pot.

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      The blue form of Agave americana looks beautiful next to the colour of terracotta.

       Conservatories

      Conservatories have never been more popular. Having a garden room attached to the house, where one can wander into a different climate and enjoy all the leafy and floral delights that are too tender for outdoors, is a splendid idea. The image often includes reclining in comfy chairs and occasionally reaching out languidly to pick a home-grown juicy citrus fruit or maybe a ripe fig. A place where the last rays of the setting sun can be observed at the end of the day …

      If only reality could match the dream. Nothing prepares conservatory owners for the difficulties of growing plants in this kind of environment. The glossy adverts are taken at face value, and the fact that there are myriad problems to overcome can be a bit of a shock. The previous pages dealt with growing plants in pots, but growing plants in pots and under glass takes the art of cultivation into a new league altogether. Plants hate the excessive heat, dry atmosphere, lack of ventilation and the extreme variations of seasonal temperatures often found in conservatories.

      The better the environment in the conservatory, the larger the range of plants that can be grown successfully.

       Choosing a conservatory

      Buy the largest conservatory that you can accommodate and afford. The larger the space, the easier it is to maintain a balanced climate. Instead of automatically siting a conservatory on the sunniest side of the house, consider a shadier spot where the heat of the summer is less intense. If possible, choose a structure with a door at each end. This will allow a good flow of air during the summer to help keep the interior cooler. Gentle breezes are what we are aiming for, not howling gales, so a sheltered part of the garden is required, not an exposed corner.

      Ventilation is a boring, but essential, subject to think about as well. It is almost impossible to have too much ventilation, especially in the summer. Most conservatories are not well designed in this department, offering just one or two feebly inadequate vents in the roof, if you’re lucky. It is worth paying extra to have as many fixed panes of glass in the roof as possible converted into movable ones that open. If the design allows, have some side vents fitted as well, to catch the breeze from all directions.

       Flooring

      As all plants are much happier growing in the ground than they are in containers, leaving some space in the conservatory floor, where small trees and faster-growing plants can be planted directly into the soil, is something worth thinking about when you are planning your conservatory. The roots would have the benefit of being able to spread out naturally, while the glass overhead would protect tender foliage from the frost.

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      Tropical, lush verdancy is what we’re aiming for in a conservatory.

      Also consider choosing the sort of flooring that can be hosed down in the summer. This would help to lessen the heat while increasing the humidity, both of which would benefit the plants. Fluffy rugs might look okay flung on the conservatory floor, but they are not exactly practical.

       Watering

      Having a hose pipe right where it is needed will make watering much less of a chore, and your plants are therefore more likely to be irrigated when they need it, rather than having to wait until it is convenient.

      Automatic irrigation systems have improved hugely during the last few years. Available from all good garden centres, they are easy to install, reliable and reasonably priced. A main pipe is placed all around the conservatory, and from this numerous drip nozzles can be pushed into each container. The timer is as easy as any domestic central heating or hot water system. They are the perfect solution for anyone who is frequently away from home or who would prefer spending their time doing other things.

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      Strelitzia reginae adds an exotic air to any conservatory.

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      The size, aspect, ventilation and maintenance of a conservatory have a direct bearing on what can be grown successfully.

       Heating

      From being boiling hot in the summer, the temperature in many conservatories plummets during the winter when the heat is quickly lost through the glass. Many plants can cope with almost freezing conditions, but a few degrees above freezing will make life more pleasant for plants and humans alike.

      Whether the conservatory is heated by leaving the door to the adjoining house open, or by radiators, hot pipes, portable gas heaters or anything else, it is important to remember that plants do not like direct heat, so keep them some distance away from any heating source. Avoid heating systems that blow hot dry air directly onto the plants’ foliage as this can make the leaves turn brown and crispy.

      If possible, avoid underfloor heating as well. Although this is nice for cats and people to walk on, plants hate this much heat so near to their