Landscaping NZ
Yates
Waimea Nurseries
Herb Herbert
Tui - A Friend In Your Garden
handy helpers

Azaleas and Rhododendrons

Azaleas and Rhododendrons are the most decorative evergreen shrubs, popular for their vivid displays of flowers from late winter to early summer.

Azalea and Rhododendron flowers come in many forms from tubular, starry, bell and bowl shaped, large and small, and even fragrant.

At a Glance:

  • Height - 50cm to 4 metres
  • Position - semi shade
  • Soil - moist, lime free, well drained
  • Flower - late winter to summer
  • Colour - pink, white, red, yellow, cream, mauve, blue, purple, orange.

Selection

Rhododendrons (pictured above) are evergreen and flower from late winter to early summer.

There are large and small flowered varieties. They grow from a height of 50cm to 4 metres. Modern varieties tend to reach only 2 metres.

Azalea indica (pictured below - left) is the best known evergreen azalea. Flowers from late winter to early summer, in coastal regions to cooler highlands. They have large flowers, small leaves and grow from 60cm to 1.2 metres in height.

Kurume azaleas (pictured below - centre) are evergreen with small leaves and small single or semi double flowers which smother the plant in spring. Kurume azaleas tolerate cooler temperatures and require less shade than indica varieties. Grow from 60cm to 1 metre in height.

Mollis azaleas (pictured below - right) are deciduous, losing their leaves in winter. Flowers appear before the foliage in spring. Some varieties are fragrant. Foliage is highly coloured in autumn. Prefers a cooler climate. Will grow in full sun to a height of 1.5 metres

When to Plant

The best time to plant is from winter to early spring, before flowering. Azaleas and rhododendrons can be planted at any time as long as they are well watered through the summer months.

Where to Plant

Plant in a moist well drained soil that has plenty of good compost (make sure the compost has no added lime in it) and organic material, dug in before planting. Raise beds in clay soil to improve drainage.

Plant in shade to filtered sunlight. Some varieties will tolerate sun.

Azaleas look great in mass plantings, mixed borders with other plants, in front of a background of evergreen shrubs or under deciduous trees.

Rhododendrons are at their best planted in mixed borders, blending in well with many other plants

How to Plant


Before planting water the plant well. Dig in plenty of good compost (make sure the compost has no added lime in it) , well rotted animal manure or organic material to the planting hole.

Refer to the Nichol’s handy helper on "How to Plant Trees, Shrubs and Roses" for more information. (CLICK HERE)

 

 

After Care …

Feeding

Rhododendrons and azaleas do not require a lot of fertiliser. 

Apply sparingly as they have very shallow surface roots which can burn easily. 

Rhododendrons and Azaleas are acid lovers - i.e. they HATE LIME! So we recommend you apply Tui Acid Fertiliser in late winter and again in mid summer.

 

Watering

Regular watering through summer is required. Deep watering is more effective than light sprinklings.

Mulching


This is essential for success!

Apply a 5cm thick layer of good compost (make sure the compost has no added lime in it) or mulch around azaleas and rhododendrons in late winter and again in mid summer to ensure roots stay cool and moist.

 



Pruning

Regular pruning is not required. However, sometimes they will benefit from being cut back.

A spindly young rhododendron can be cut back by one third of its length, above a bud, in late winter early spring. Pinch young shoot tips to encourage bushy growth.

Pests and Diseases

Thrips  are small black sucking insects that cause speckled silvery leaves. Spray with Mavrik or Confidor.

Mites are minute sucking insects found on the underside of leaves that cause distortion, speckling and silvering of leaves. Spray with Mavrik.

Aphids are small sucking insects on new growth. Control with Confidor.

Leaf Roller Caterpillars chew holes in leafs and flowers and roll themselves up in the leaves with webbing.  Squash the caterpillar with fingers, or spray with Mavrik.

Powdery Mildew makes the leaves generally appear smaller, off-colour and the underside of the leaves are covered in a powdery like substance.  Try to improve air circulation around the plant. Spray with Yates Fungus Fighter.

Alkaline Soil - If the soil is too alkaline yellow patches appear between the veins. Use Tui Acid Fertiliser to correct this.

            Autumn is the best time to sow a NEW LAWN and rejuvenate an old lawn. Lawns establish better from March to mid April when the autumn rains will soak well into the soil while it is still warm.

                First remove all perennial weeds, such as couch and dock, with a fork and then with a rotary hoe cultivate a seed bed about 20cm deep. Hollows and high places must be levelled out. Use a long board as well as much tramping with your heals - this will find all the soft spots that would sink and create hollows after the very first rain. A roller is not suitable at this stage for developing a level surface as it will simply roll the mounds and straddle the low bits.

                Most lawns are sown with fine leafed grass seed such as Fescue and Browntop and this is fine for a show lawn. But for a hard wearing lawn that will take the punishment of family cricket and playful dogs select a lawn mixture that contains some Rye in the mix. Clover is not recommended in a good lawn as it produces a large head of leaves that spread over a largish area in summer then shrinks back in winter, allowing weeds to take over before the clover re-grows.

                Because the seed is so small divide the whole lot into four parts and sow up and down the area then across as well as diagonally for an even coverage. Rake the seed in very lightly and roll. Moisten each morning to stop the birds from enjoying wonderful dust baths and you will find cats are not fond of digging damp soil either. Moisture is also vital for germination.  When the grass is 6cm to 8cm high it may be cut with a lawn mower set high.

                OLD LAWNS that are only slightly uneven and have good grass can be transformed into a really nice lawn. Spray out dandelions and daisies and 

            Autumn is the best time to sow a NEW LAWN and rejuvenate an old lawn. Lawns establish better from March to mid April when the autumn rains will soak well into the soil while it is still warm.

                First remove all perennial weeds, such as couch and dock, with a fork and then with a rotary hoe cultivate a seed bed about 20cm deep. Hollows and high places must be levelled out. Use a long board as well as much tramping with your heals - this will find all the soft spots that would sink and create hollows after the very first rain. A roller is not suitable at this stage for developing a level surface as it will simply roll the mounds and straddle the low bits.

                Most lawns are sown with fine leafed grass seed such as Fescue and Browntop and this is fine for a show lawn. But for a hard wearing lawn that will take the punishment of family cricket and playful dogs select a lawn mixture that contains some Rye in the mix. Clover is not recommended in a good lawn as it produces a large head of leaves that spread over a largish area in summer then shrinks back in winter, allowing weeds to take over before the clover re-grows.

                Because the seed is so small divide the whole lot into four parts and sow up and down the area then across as well as diagonally for an even coverage. Rake the seed in very lightly and roll. Moisten each morning to stop the birds from enjoying wonderful dust baths and you will find cats are not fond of digging damp soil either. Moisture is also vital for germination.  When the grass is 6cm to 8cm high it may be cut with a lawn mower set high.

                OLD LAWNS that are only slightly uneven and have good grass can be transformed into a really nice lawn. Spray out dandelions and daisies and rake or scarify up old thatched grasses that tend to choke out a lot of lawn grass which is often the cause of a thin patchy lawn. Fill in the low areas with soil and tramp, rake, level and sow lawn seed. Scatter some seed over scarified area and sprinkle a little top soil on top of the seed and keep it moist to help the germination.

            If GRASS GRUB has been a problem in the past, attack these pesky pests immediately. Many families of young grubs are silently underground eating the grass roots and it is not until the damage has already been done that we notice the destruction. If damage is already beginning to show sprinkle Soil Insect Killer over the lawn on a mild dewy night.

rake or scarify up old thatched grasses that tend to choke out a lot of lawn grass which is often the cause of a thin patchy lawn. Fill in the low areas with soil and tramp, rake, level and sow lawn seed. Scatter some seed over scarified area and sprinkle a little top soil on top of the seed and keep it moist to help the germination.

            If GRASS GRUB has been a problem in the past, attack these pesky pests immediately. Many families of young grubs are silently underground eating the grass roots and it is not until the damage has already been done that we notice the destruction. If damage is already beginning to show sprinkle Soil Insect Killer over the lawn on a mild dewy night.