The National Begonia Society




Tim Jemmott

Begonia Species



The February has been bitterly cold. I've only had to water my begonias twice or less in some cases in the last month. Temperature is just one factor determining how frequently plants should be watered.

Over watering is said to be the most common cause for the death of house plants. I have been guilty of this error several [many] times. Unfortunately an over watered will droop much like a plant that needs water.

Temperature, humidity, air movement, pot size and shape, drainage and potting medium are all factors that will effect how frequently plants will require watering. Usefully for us the majority of begonias can be grown under standardised conditions.

The compost should be allowed to dry between watering. The rate at which water will drain and evaporate from a pot will be determined by the size, shape, what the pot is made of, the temperature, air movement around the pot as well as the potting medium itself.

    Small pots dry out faster than large pots.
    Clay pots will dry out faster than plastic pots.
    Shallow pots [ pots] will dry out faster than standard pots due to there large surface area in relation to the volume.
    A pot in a draft or by a fan will dry out faster [due to the drop in relative humidity around the pot] than a pot in a more shelter position.
    Pot weight can also be a good indication as to how much water is in the pot. This is more useful with plastic pots.

You can grow most begonias in any commercially available potting compost. They tend to prefer a peat based compost. Added horticultural grit and or perlite to improve the drainage. Compost with additives to retain water probably should be avoided. In his book Mark Tebbitts suggested this mix;

    7 parts peat
    2 parts horticultural grit
    1 part orchid bark
    a little slow release fertilizer
    a little ground limestone

I found this mix stayed wet for too long for my conditions. As my greenhouse faces west in the winter and spring it can take a while to warm up in the morning. I am currently using a mix of;

    5 parts peat
    2 parts horticultural grit
    2 parts pearlite
    1 part orchid bark
    a little slow release fertilizer

This mix dries out a little bit quicker.

Last week I took a day trip to Glasgow Botanic Gardens to see the National Collection of Begonias. The Botanic Garden are on the western side of Glasgow, the glasshouse dates to 1839 . I have always enjoy visiting glasshouses the Main Ranges at Glasgow reminded me greatly of the old glasshouse at RHS gardens at Wisley with lots of nooks with interesting plants to find. The orchid house is very interesting.

The National Collection of Begonias is housed in one corner of the glasshouse known as the Main Ranges [restored 2004].  Its a large mixed collection [>400 taxa] of all types and forms of begonias [species, hybrids, cane-stems, shrub-like, trailing/scandent and rhizomatous] from all over the world. There were several plants in the section Gireoudia that I have only read about. I was particularly interest in B. breedlovei which is a plant I'm growing from seed. I knew from its description in a paper by Kathleen Burt-Utley that it was a large plant, but, it is far more impressive than I had imagined.

I thoroughly enjoyed my visit to the National collection of begonias at Glasgow Botanic Gardens and would recommend it to anyone who is interested in begonias.

Glascow botanic garden

Main ranges

Inside GBG

Inside begonia house

Inside begonia house

Inside begonia house

Inside begonia house

B sizemoreae

B goegoensis

 B acetosa

B imperialis

B breedlovei

Diary Introduction

April     May

B breedlovei

B breedlovei seedling

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