How to Grow Sensitive Alpines Without an Alpine House

Alpine houses provide specialist conditions needed for growing alpine plants, such as high light levels, good air flow and protection from winter wet.

But if you don’t have an alpine house, is there anything you can do instead to grow sensitive alpine plants? Yes, there is!

While possibilities are certainly more limited without a specialist plant house, there are tips and tricks you can try at home to grow beautiful alpine plants in your garden.

What should I do if I can’t have an alpine house?

There are many growers who would aspire to having an alpine house but who don’t have the money or space to do so.  Others may have a greenhouse but want to grow a wider variety of plants of the type that would perish over winter in the cold, airy, bright conditions of a pure alpine house.

Here are some alternative options for a small collection of alpines outdoors or in a standard greenhouse or frame.

Can I provide extra protection to my outdoor pots, troughs and rock garden plants?

It is possible to provide tailored protection to those plants you’re most worried about. Many alpines will perform well outside with just a little help to protect them from winter wet.

A good example is the raoulia australis growing in my rock garden.  It may survive the winter wet but it has spread attractively and I don’t want to risk parts or all of it being damaged in heavy winter rain.  I sandwich a sheet of perspex between bricks keeps even the heaviest downpour from drenching the plant.  The sides are open allowing airflow.

Alpine growers without an alpine house often build more elaborate frames over their plants.   They place potted plants in more sheltered positions such as at the base of walls, in open car ports or the protruding eaves of sheds or houses.

Can I use a frame instead?

If you don’t have the funds or the room for an alpine house a frame will provide a bit more protection for your alpines.  I have some plastic recycled cold frames that I use as sand plunge beds for potted snowdrops and alpine seedlings.  I am propagating bulbils from some of my spring bulb collection in pots in there, and use them in summer for some of my dormant potted spring bulbs.

The frames are kept open all year round to ensure maximum air flow.  They are only closed if I think the heavy raindrops could damage the plants.  Not all alpines will survive well in a frame but you will definitely expand the range of what you can grow if you use a frame.

Can I use a polytunnel?

Polytunnels are cost effective alternatives to greenhouses and have many uses.  It is generally considered that they aren’t good for alpine growing.  The main reason for this is that the polythene covering lets less light through than clean glass and the lack of side vents mean they are prone to overheating and high humidity.

Having said that, some growers do make a success of growing alpines in tunnels, and pay special attention to creating good air flow.  Using modern tunnel skins made of more reflective materials can help and other adaptations to consider would be installing fans or using sides made of netting rather than plastic to allow additional air flow.  The pictures below show the collections of David Carver.  He uses a large polytunnel for his beautiful alpine plants and ensures good air flow using additional side vents.

Positioned in a shady position, polytunnels are also very useful for growing woodlanders such as shortias or hepaticas.

How to use a standard greenhouse for alpines and bulbs

I am lucky to have a beautiful greenhouse but I like to grow tropical plants that need some warmth over winter.  It’s useful for growing seedlings and also enjoy growing tomatoes and greenhouse fruits.  My greenhouse needs to be multi-purpose.

It is possible to use a standard greenhouse to grow some alpines but you will need to think carefully about ventilation and shading and only grow them in the airiest places and where they won’t overheat in a hot summer.

Experimental greenhouse sand plunges

I am experimenting with growing a few alpine treasures in my greenhouse.  Old wine boxes filled with sand act as plunge beds.  They are placed in front of the large vents so that air flows over them throughout the year.  The vents are opened each day in winter for maximum ventilation, unless the temperature is so low it would damage other plants.  The overhead shades are used in summer and this ensures the greenhouse doesn’t get too hot.

Few of these plants need to be indoors but many just perform better there.  An example is the lewisias.  They can be grown outdoors but don’t like direct wet.  I find they just look and perform better under glass.

Table top seasonal displays

During winter I also put a small table in front of the greenhouse door, which is then opened most days.  I use the table to display pots of flowers and bulbs as they come into growth.  Examples include potted snowdrops, miniature narcissi, primula auricula, and cyclamen.  This provides a beautiful display for the family to enjoy and to coax me out of the house, even on a dull wet day.

I still dream of an alpine house but for now I’m able to sate my love of alpine plants indoors and out.

With thanks to…

Dr Adrian Cooper, Amanda Whittaker, Linda Lane and David Carver for sharing information on alpine houses and specialist plant houses.

Dr Adrian Cooper is the show secretary for the Alpine Garden Society and grows a huge range of alpines in his garden and alpine house.

Amanda Whittaker is the National Collection holder of crassula.

David Carver is a member of the South Devon and Exeter AGS groups and keen alpine grower.  He also has a growing collection of daphne cultivars.