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All, Spring

Growing Rhododendrons

August 31, 2021

Growing Rhododendrons

Growing Rhododendrons

In order for Rhododendrons to develop successfully in colder climates they need:

  • Porous or acidic soil.
  • To be planted in an area that receives morning sun with shade in mid to late afternoon (shade tolerant, not shade loving).
  • Protection from winter wind (do not plant in open areas unless well protected with burlap screening).

  • The hole for planting must be 15 cm deeper than the root ball and 2 to 3 times wider.
  • Loosen the soil in the hole (do not remove).
  • Make raised bed with 50% Parkwood® 3 in 1 Planting Mix (compost can also be used) and 50% Peat Moss.
  • Do not plant deeper than what the plant was in the nursery container.
  • Carefully remove the plastic or metal container (if your pot is fibre you need only remove the rim and bottom). If your plant is balled and burlapped (B&B) untie knots and pull burlap back from the stem once the plant is placed.
  • Before planting, loosen roots carefully by hand if they are circling soil.
  • Ensure soil mixture is compact around the root ball.
  • Water thoroughly and fertilize with Parkwood® Flower Plant Food 15-30-15.
  • Well drained, yet moist acidic soil with high organic matter.
  • Sandy loam with added peat moss is ideal.
  • Mulch with shredded bark, cocoa beans or a mixture of peat moss and compost.
  • Do not cultivate around plants, remove any weeds by hand.
  • Water only when soil has dried out. Soak thoroughly using a gentle overhead sprinkler or soaker hose on the surface.
  • Check moisture levels weekly (more if weather extremely hot).
  • Ensure soil is moist before the ground freezes in the fall.


  • Fertilize in early spring (as soon as soil warms up and root growth begins).
  • Parkwood® All Purpose Plant Food 20-20-20 followed according to the package directions.
  • Fertilize again once new growth has matured with Parkwood® Water Soluble Fertilizer Flower Food 15-30-15. This will encourage new bud growth for the following year.
  • Iron deficiency can result from high soil pH and can be corrected by acidifying the soil with peat moss for a long term green colour. In short term, plants can be sprayed with Iron Chelate.
  • Do not use Aluminum Sulphate to acidify the soil as it leaves build up in the soil and will cause harm to your plants over time.
  • Very little pruning is required unless your plant becomes uneven or grows over a walkway. This can be done while plants are in bloom if you would like the cuttings.
  • Greater branching can be encouraged by removing the centre bud of the leaf bud clusters in late fall.
  • Dead-Heading is the removing of finished flower clusters; doing this will encourage flower production for the following year.
  • Use a burlap screen, staking four corners and an opening left at the top to ensure the burlap does not touch the plant.
  • Leaves or cut up evergreen boughs can add extra protection around the base of the plant.
  • Spray an anti-desiccant such as Wilt-Pruf.
  • Deciduous Azaleas add additional colour (yellow and orange).
  • Mountain-Laurel (Kalmia) and Pieris add different foliage texture and will flower in any partially shaded area.
  • Wintergreen (Gautheria procumbens), Bunchberry (Cornus canadensis) and Twinflower (Linnaea b orealis) are an excellent ground cover for moist acidic soil in shaded areas.
  • Hardy Ferns, Primulas, Columbines, Daylilies, and various wildflowers such as Trilliums, Foam-flower, Virginia Bluebell, and Jack-in-the-Pulpit can also add interest and should be planted at the same time so as not to disturb the surface roots of plants after they are established.