Gardening

Gerry Daly tells us why there is nothing to beat the beauty of Rhododendrons and gives us some tips for this month in your garden.
 
 
 
 
 
 

Rhododendrons Unsurpassed!
It may be a big statement to make, but really, it’s true: there is nothing to beat the beauty of rhododendrons in full flower, and there are rhododendrons for even the smallest garden. Go and see some of the giants in the big gardens open to the public, such as the National Botanic Gardens in Glasnevin, Fota in Cork, Muckross in Killarney or Glenveagh in Donegal. These are the big Himalayan rhododendrons, trees in size, reaching fifteen metres tall and as much as double that across - so big that crows have been known to nest in them.

While these large plants offer a tremendous blast of blazing red, yellow, pink or white, they are much too big for ordinary gardens, and in any case, they can take a hundred years or more to reach the massive size of which they are capable. But there are many smaller kinds that grow perhaps two or three metres tall and can be accommodated easily in an average garden. These are widely available and many different varieties are on offer, such as ‘Crest’, yellow, ‘Mrs Furnival, pink, ‘Nova Zembla’, red and ‘King George’ with pink buds opening white and fragrant.

Then there are the really small kinds, such as the yakushimanum hybrids, some of which are named after the Seven Dwarfs, ‘Grumpy’ being one of the more popular ones. These, and others such as ‘Ruby Heart’ and ‘Baden Baden’, both red, make small neat, rounded bushes that cover themselves with flowers and look good all year round with dark green foliage. These could even be grown in large pots on a balcony or a small city courtyard.

Growing in pots is a possibility too where the soil is limy, because these rhododendrons do not like limy soil. Only the smaller kinds can be grown in pots, however, and if the soil is limy and you wish to grow the larger kinds, then the soil must be acidified by adding about 100 grams per square yard of sulphate of iron and top-dressing with about 10 centimetres of organic material, ideally the fallen leaves and decayed debris from under pine trees or any conifer.

This Month in your Garden...

• Re-pot any house plants that have become pot-bound
  
• Sow sweet peas directly outdoors for late flowers
  
• Plant out summer bedding in good conditions in late May
  
• Keep a careful watch for greenflies on roses and fruit trees
  
• Thin out vegetable seedlings as soon as they are big enough
  
• Plant out canna lilies, gladiolus and dahlias for late summer flowers
  
• Continue to spray apple and trees for apple and pear scab disease
  
• Remove rose suckers as soon as they appear at the base of the bush
  
• Increase the regularity of lawn mowing, during rapid growth
  
• Apply shading to greenhouse glass to prevent leaf scorching
  
• Carry out lawn seeding for a new lawn, or re-sow an old one
  
• Sow hardy annual flower seeds for late summer colour
  
• Spray roses regularly against rose blackspot disease
  
• Prune early-flowering shrubs as soon as they finish
  
• Apply lawn fertilizers, if the grass is not a good colour
  
• Sow seeds of wallflowers, stocks and sweet william for next year
  
• Apply lawn weedkillers now in fine weather for best results

Using Garden Tools

Garden hose
This month the garden hose comes into its own. Until now, the amount of watering required has been negligible but containers must be watered. Young plants planted out this spring, and last autumn and winter, are also making demands for more water than can be supplied easily with a watering can. A hose is a quick way to carry out watering and to make sure that plants are adequately watered. A hose can be messy left lying around, and even dangerous to the unsuspecting. So it is important to roll up the hose after use. There are some proprietary roll-up systems that are handy, or simply roll it by hand.

Care for the environment:
Vine weevil control

Vine weevil grubs often attack plants in pots and containers and can do serious damage. There are chemicals for control and also eelworms that are natural enemies and these two remedies available from garden centres work very well. However, ordinary, unsterilised garden soil has a battery of vine weevil enemies - from black beetles that eat the eggs to fungi and ‘wild’ eelworms that parasitize the young larvae. By using about half the volume of good garden soil with compost, and thoroughly mixing the two, a very good measure of control can be achieved without environmental impact, no cost of control products, and a reduced cost for compost!