Vulcan Rhododendron

Rhododendron hybrid ‘Vulcan’

Vulcan Rhododendron

Rhododendron hybrid ‘Vulcan’

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 Vulcan Rhododendron grows to be a rounded, evergreen shrub 5 feet tall and wide within 10 years. It will ultimately reach 8 feet and be up to 10 feet wide. In late spring it is smothered in huge bunches of large, blood-red flowers that turn it into an inferno of color. This substantial shrub is perfect for the back of borders or beneath tall deciduous trees, and its large, dark green leaves always look attractive and interesting. Use it around your home, in beds, or in wooded areas. We recommend it for the southeast, where it tolerates hot humid summers better than just about any other variety.

  • Spectacular blood-red blooms in large trusses
  • Handsome dense, rounded form growing to 5 feet and more
  • Showy large leaves are attractive all year
  • Excellent choice for hotter zones
  • Grows well in partial shade beneath trees

The Vulcan Rhododendron will grow across a wide part of the country, from zone 5 to 8, and to zone 9 in the northwest. Plant it in full sun in cooler areas, or anywhere in partial shade with morning sun, or in the dappled shade beneath deciduous trees. The soil should be moist, well-drained and rich in organic material. It should be acidic, and most soils in the east are suitable. If you have clay soil, use plenty of organic material and plant in a raised bed. In planters and tubs use potting soil blended for acid-loving plants.

Plant Hardiness Zones 5-9
Mature Width 5-10
Mature Height 5-8
Sun Needs Full Sun, Partial Sun
Zones 5-9

If you want a truly special garden, with glorious blooms and durable evergreen foliage that gives it structure and class, there is a simple way – grow rhododendrons. If you have suitable acidic soil you can have beds of color in spring that are unrivalled by any other shrubs, and after a few years they will have grown into sturdy mounds of foliage that look great all year round. If your soil is not suitable, consider planting them in tubs and large pots, where they will thrive and grow well for many years. Either way, to give your garden that quality look you see in magazines, rhododendrons are the way to go. Many are in delicate tones of pinks, lilacs and purples, but for a real punch of color plant the Vulcan Rhododendron. Named after the Roman god of fire and volcanoes, this medium-sized shrub really does blaze out like an inferno, glowing a clear, rich red across your garden. Best of all, if you live in zones 8 and 9, especially in the southeast, this tough plant is for you, resisting heat and humid extremely well.

Growing the Vulcan Rhododendron

Size and Appearance

The Vulcan Rhododendron is a broad, mounding shrub, with large evergreen leaves on many branches, forming a dense plant. It will grow 5 feet tall and wide within 10 years, eventually reaching as much as 8 feet tall and up to 10 feet wide. When planting, think ahead to when it will be larger, and leave enough room for it to mature. The very dark-green, oval leaves have a smooth, slightly lustrous surface, and they are almost 5 inches long and 2½ inches wide, growing in radiating clusters at the ends of every branch. Leafy branches grow right to the ground, so this plant needs nothing in front, and looks perfect as a specimen.

Flowering takes place in late spring, which is perfect, as it extends the season, and every branch ends in a large cluster of about 10 blossoms. Each one is funnel shaped, with elegant fluted, wavy edges, and over 2 inches across. They are a rich, bright blood-red color, with no hints of pink or purple – a pure red that really does live up to its fiery name.

Using the Vulcan Rhododendron in Your Garden

This evergreen shrub has a bold but neat form, so it is ideal for planting around your home. Why not use flowering plants rather than clipped evergreens for foundation planting? When not in bloom its large leaves make a solid mound, always looking great. Plant it at the back of smaller beds, and in the middle of larger ones, or as a specimen, alone or in a cluster, beneath large trees out on your lawn. It is as perfect for planting at the edges of natural wooded areas as it is for the most formal garden. Planted in large tubs it can be used at the corners of a terrace or patio, along a path, or standing in beds.


The Vulcan Rhododendron is perfectly hardy in zone 5, and it thrives in zones 6, 7 and 8, as well as in zone 9 in the pacific northwest. Rhododendrons are difficult in the southeast, especially in zone 9, but this one is tried and tested for heat and humidity, and it is our top-pick variety for the South.

Sun Exposure and Soil Conditions

Plant the Vulcan Rhododendron in full sun in zone 5, or in partial shade there, and in all other zones. Some afternoon shade, or light dappled shade beneath deciduous trees is ideal. The soil should be rich in organic material, and moist but well-drained. It should also be acidic, with a pH value below 6.5. In hot zones, avoid planting in clay soil, or enrich it heavily with lime-free organic material and plant in raised beds, as good drainage is very important for rhododendrons.

If you don’t have acidic soil, plant in a tub or large pot. Rhododendrons have a fibrous root system that adapts well to pots, and plants will live for many years, and grow to a good size. Make sure your pot has a drainage hole and don’t place it in a saucer. Use a potting soil blended for acid-loving.

Maintenance and Pruning

The Vulcan Rhododendron needs no significant maintenance. The only annual job is to snap off the flower spikes once blooming is over. This prevents seeding and encourages more buds for the next year. Don’t remove any foliage when doing this, just the flower spike. Pruning and shaping is not necessary. Keep well-watered during dry weather, as this plant is not drought resistant. Pests and diseases are rare and normally not a problem.

History and Origin of the Vulcan Rhododendron

The nursery called John Waterer and Sons, in the UK, was established in the 18th century and owned by a succession of family members until it closed during WWII. There were two main nurseries, and over the years they created over 200 hybrid rhododendrons of great beauty. One of the nurseries was at Bagshot, in Surrey, southwest of London, and it was there that the variety called ‘Vulcan’ was created. They took an earlier hybrid they had made in the 1920’s, called ‘Mars’, with deep crimson flowers, and crossed it with a wild rhododendron species from the mountains of southern China and Burma, Rhododendron griersonianum, which also has red flowers. They released ‘Vulcan’ in 1938, but because of the closing of the nursery a few years later it was not officially registered until 1958.

Buying the Vulcan Rhododendron at The Tree Center

More brilliantly colored and more showy than either of its parents, the Vulcan Rhododendron has proved its value for more than 80 years. It received an Award of Merit from the Royal Horticultural Society in 1957 – a clear stamp of approval. It is consistently recommended for hot areas, so choose the best, but choose it now, because our stock of these beautiful plants will soon be gone.

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Vulcan Rhododendron

Rhododendron hybrid ‘Vulcan’