Rhododendron 'Tropic Glow'

An evergreen shrub growing to around 2m tall and 1.5m wide.

Produces trusses of bright orange flowers with a yellow throat through spring. Leaves are mid green and leathery.

Prefers partial or dappled shade in well-drained soil. They prefer a restricted root zone and unlike other hardier rhododendrons require protection from frost.

Always choose healthy well grown plants and plant after autumn rains as the soil is moist and warm and allows plants to become established before winter. This enables them to withstand dry periods during the following summer. Young plants require thorough watering during dry periods over the first two or three years mulching helps to conserve moisture and suppress weeds.

Rhododendron need open organic or friable soil. They have very fine roots which will not thrive in the heavy clay common in parts of Auckland concrete hard in summer and sodden and root rotting in winter. If the clay is very heavy form raised beds or an individual planting site with the rootball completely above the clay; add extra topsoil and incorporate coarse sand, bark or other organic matter or use one of the special Rhododendron mixes which are available. Ponga logs make an attractive surround to raise planting sites. On a slope, a shelf may be cut to help locate the plant but never dig into clay as it traps water and rots roots. When planting in average or volcanic soils keep the top of the rootball level with the soil surface. However, if the soil remains sodden for an hour or so after heavy rain form raised planting sites as above. Generous applications of pine bark mulch keep the roots cool and retain water.

Before planting ensure the root ball is saturated and remove the planter bag or pot with minimal root disturbance. Trim any broken roots and plant at the same level as in the container. Dig a hole twice the diameter of the root ball and firm in and water once planted. Make sure plants are watered well until established if planting in a drier period. Plant with some general slow release fertiliser and then every spring apply an organic based fertiliser such as blood and bone at a handful per square meter as new growth. The worst fate for a tree is to be planted in a hole where the root ball is allowed to sink below the surrounding ground level. Therefore it is generally desirable to plant trees into slightly raised beds of well cultivated soil. This improves drainage and provides near surface roots with well aerated soil in which to grow.

Mulching annually helps suppress weeds and conserve moisture. Organic materials such as sawdust and bark contribute to soil structure as they decompose but keep mulching material away from the trunk. Rhododendrons need good rainfall during spring and summer and perform best in a drier winter than is usual in Auckland. Water new plantings thoroughly during dry periods in spring and summer. Heavy watering or rainfall causes no problems provided water drains away freely. When choosing fertiliser use one specially formulated for "acid-loving" plants. Make applications of 25g/m2 in early and late spring. If the soil is very acid apply dolomite lime. Generous applications of pine bark mulch keep the roots cool and retain water. Sprinkle evenly and work into the top 2 to 3cm of the soil taking care not to damage surface roots.

The first summer and autumn after planting is critical for young plants; water thoroughly during dry periods. Pests and diseases can have serious debilitating effects on young plants; check regularly. Check stakes and ties for chafing and constriction and remove as soon as plants are strong enough to withstand winds without damage.

Prune after flowering to maintain the shape and promote new growth. Fertiliser can be applied in early and late spring. Choose a fertiliser for "acid-loving" plants. Pruning in the early years when the plant is still small may just be a matter of gently snapping off the old flower heads so the leaf buds below can burst open easily. If major pruning is required then vireya rhododendrons will tolerate moderately hard pruning.

Relatively free of pests and diseases.

Palm Garden