White Bloom-A-Thon® Azalea

Rhododendron hybrid 'RLH1-3P3' (PP# 21,512)

White Bloom-A-Thon® Azalea

Rhododendron hybrid 'RLH1-3P3' (PP# 21,512)

This product is currently out of stock and unavailable.


How are the heights measured?

All tree, and nothin' but the tree! We measure from the top of the soil to the top of the tree; the height of the container or the root system is never included in our measurements.

What is a gallon container?

Nursery containers come in a variety of different sizes, and old-school nursery slang has stuck. While the industry-standard terminology is to call the sizes "Gallon Containers", that doesn't exactly translate to the traditional liquid "gallon" size we think of. You'll find we carry young 1-gallons, up to more mature 7-gallons ranging anywhere from 6 inches to 6ft.

How does the delivery process work?

All of our orders ship via FedEx Ground! Once your order is placed online, our magic elves get right to work picking, staging, boxing and shipping your trees. Orders typically ship out within 2 business days. You will receive email notifications along the way on the progress of your order, as well as tracking information to track your plants all the way to their new home!

Why are some states excluded from shipping?

The short & sweet answer is: "United States Department of Agriculture Restrictions." Every state has their own unique USDA restrictions on which plants they allow to come into their state. While we wish we could serve everyone, it's for the safety of native species and helps prevent the spread of invasive disease & pests. We've gotta protect good ole' Mother Nature, after all.

About Me


The White Bloom-A-Thon® Azalea is smothered in snow-white flowers for months and months. It blooms in April and May, and then begins again in July, increasing through September and October right up to the first hard frost. This compact evergreen bush grows just 2 or 3 feet tall and wide, making it perfect for the front of beds, edging paths or planting beneath mature trees. It is also an ideal pot plant for your terrace, porch or patio.

  • Clusters of beautiful pure-white flowers for months
  • Spring blooming, followed by more in summer and fall
  • Reliable reblooming even in full shade
  • Cold hardy in zone 6
  • Great for pots and planters

Grow the White Bloom-A-Thon® Azalea in partial or full shade, with this group of azaleas being among the best for shadier beds. It is hardy in zone 6, and it takes the summer heat of warmer zones well. The soil should be moist, well-drained and enriched with organic material. It also needs to be acidic, with a pH value of 5.5 or less. If you don’t have suitable soil, use pots filled with soil for acid-loving plants. Pests and diseases are rare, and a single annual trim in early summer is all the care it needs.

Plant Hardiness Zones 6-9
Mature Width 2.5-3
Mature Height 2.5-3
Sun Needs Partial Sun, Shade
Zones 6-9

Do you like white flowers? Then you have come to the white place. The Bloom-A-Thon® azaleas are renowned for giving us 20 weeks a year of blooms, and the White Bloom-A-Thon® Azalea is no exception to that. White is such a gorgeous color for the garden, especially in shadier spots, which is exactly where these azaleas thrive. Instead of disappearing into the shadows, white glows out like starlight, and looks best in shade or evening light, when most other flowers look dull. If you work away from home all day, or like to use your garden in the evenings, then white flowers make a lot of sense. Plus, they fit in with every other color, so no clashes, and they make your other colors look even better. Why not create a cool and sophisticated white garden under your trees? There are lots of white flowers and white-variegated plants to grow in it, and of course the White Bloom-A-Thon® Azalea will be a big part, blooming continuously month after month.

Growing the White Bloom-A-Thon® Azalea

Size and Appearance

The White Bloom-A-Thon® Azalea is a low, mounding shrub growing no more than 2 to 3 feet tall and wide. It has dense branching, so it stays bushy and neat, needing no trimming to keep it that way. The small leaves are only ½ to 1½ inches long, and neat dark-green ovals. They have a soft feel because of the many short soft hairs they are covered with.

Blooming begins in April or May, on buds that were formed late in the previous year. This first blooming is profuse, and it lasts 4 weeks or longer. Then the bush takes a short rest, while new shoots grow, and then by July in most areas those new stems begin to bloom. Blooming increases steadily, until by September and into October it is extensive, and often lasts until the first hard frost brings the season to an end. Every stem carries 2 or 3 buds at its end, and these produce about 3 flowers each, so up to 10 blooms can develop in succession at the end of a single stem. Each bloom lasts up to 10 days, so you can see what a prolific and profuse display you will see. The single blooms are like open trumpets, up to 3 inches across, with a smooth, velvety texture and flamboyantly ruffled edges. Both inside and outside the flower is a pure, snow-white, with just a scattering of dark spots deep in the throat, to give depth. Flowers drop cleanly, without any dead-heading being needed.

Using the White Bloom-A-Thon® Azalea in Your Garden

The lower size of this bush makes it ideal for smaller gardens, or for edging your garden beds, or turning the corner of a pathway. Plant them 2 feet apart for a continuous border – perhaps with other colors from the taller plants in the Bloom-A-Thon® range behind, in a gorgeous bed of endlessly blooming azaleas. It is also ideal for pot culture, planted in boxes, in pots up a stairway, or on a table in a porch or lanai.


This White Azalea is hardy even in zone 6, and it has excellent winter retention of foliage, with just a few leaves possibly dropping from the center of the plant in the coldest zones. It also has excellent resistance to heat, so it grows just as well in all the hot zones.

Sun Exposure and Soil Conditions

Grow the White Bloom-A-Thon® Azalea in partial or light full shade. Morning sun and afternoon shade is ideal, but these plants are well-adapted to growing in more shade, and still rebloom reliably. The best soil is moist, well-drained, rich and acidic, with a pH of 5.5 or less. Enrich planting areas with lime-free organic material. If you don’t have suitable soil, grow in pots or planters, using soil for acid-loving plants. Azaleas have fine roots and live comfortably in pots for many years.

Maintenance and Pruning

Use mulch over the roots to conserve moisture, and water regularly during dry periods. Feed with azalea food, especially when growing in pots. We recommend a light trim after the spring blooming, to remove seed pods and encourage new stems. It is at the end of those shoots that new flowers will form. You will notice buds in late fall no longer opening. This is normal, and those buds will give the early spring blooms of the next year. Don’t trim in summer or fall, or before the spring flowering begins.

History and Origin of the White Bloom-A-Thon® Azalea

Robert Head is America’s expert on reblooming azaleas, and he created not only the Bloom-A-Thon® range, but the ReBLOOM™ varieties as well. The exclusive range of Bloom-A-Thon® azaleas all have crisp, clean colors, good winter hardiness and compact growth. Robert Head began with many older varieties that show a slight tendency to rebloom, and by crossing them he built up over the years a large collection of promising plants. It was one of those that he used to make the White Bloom-A-Thon® Azalea. In 1996, he pollinated a plant code-named RLH-1800-WS with pollen from an older azalea variety called ‘September Song’, and in 2000 the seedlings he grew began to bloom. One had gorgeous white flowers, and after further trials and study it was patented in 2010 with the official name of `RLH1-3P3`. It is one of the five varieties available in the Bloom-A-Thon® range, which is distributed to nurseries by Proven Winners®, a brand managed by Spring Meadow Nursery and owned by a group of major US wholesale growers.

Buying the White Bloom-A-Thon® Azalea at The Tree Center

There is no doubt that white is the most useful color in the garden, and the best gardeners use it profusely. You can too with the White Bloom-A-Thon® Azalea, and you will love the months of bloom you get from just this one plant. Order right away, though, while you still can, as our limited stock will be gone very soon.

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White Bloom-A-Thon® Azalea

Rhododendron hybrid 'RLH1-3P3' (PP# 21,512)