North America Non-native Plant

Casia Amarilla

Botanical name: Senna spectabilis var. spectabilis

USDA symbol: SESPS3

Native status: Not native but doesn't reproduce and persist in the wild

Synonyms: Cassia carnaval Speg. (CACA92)  ⚘  Cassia spectabilis DC. (CASP12)   

Casia Amarilla: A Golden Beauty for Warm Climate Gardens If you’re looking for a show-stopping flowering tree that can transform your landscape into a golden paradise, let me introduce you to casia amarilla (Senna spectabilis var. spectabilis). This tropical beauty might not be a household name, but once you see ...

Casia Amarilla: A Golden Beauty for Warm Climate Gardens

If you’re looking for a show-stopping flowering tree that can transform your landscape into a golden paradise, let me introduce you to casia amarilla (Senna spectabilis var. spectabilis). This tropical beauty might not be a household name, but once you see its brilliant yellow blooms cascading from graceful branches, you’ll understand why it’s worth considering for the right garden.

What Makes Casia Amarilla Special?

Casia amarilla, also known by its scientific name Senna spectabilis var. spectabilis, is a member of the legume family that knows how to make an entrance. When this tree decides to bloom, it doesn’t hold back – clusters of bright golden-yellow flowers cover the canopy, creating a spectacular display that can be seen from quite a distance. The compound leaves provide an attractive backdrop year-round, giving the tree a delicate, almost feathery appearance.

You might also encounter this plant listed under its older names, including Cassia spectabilis or Cassia carnaval, but don’t let the name changes confuse you – it’s the same gorgeous tree.

Where Does It Come From?

This golden wonder hails from tropical South America, where it grows naturally in the warm, humid climates of Brazil and Argentina. In its native range, it’s perfectly adapted to seasonal rainfall patterns and consistently warm temperatures.

Is Casia Amarilla Right for Your Garden?

Here’s where we need to get practical about expectations. Casia amarilla is definitely not a plant for everyone or every climate. This tropical native thrives in USDA hardiness zones 9b through 11, which means if you’re dealing with anything resembling a real winter, this tree won’t survive outdoors year-round.

However, if you live in South Florida, Hawaii, Southern California, or other consistently warm regions, this could be an excellent addition to your landscape. It works beautifully as:

  • A specimen tree in large gardens
  • Part of a tropical landscape design
  • Shade tree for patios and outdoor living spaces
  • Street tree in appropriate climates

The Wildlife Connection

One of the lovely things about casia amarilla is its appeal to pollinators. The abundant yellow flowers are magnets for bees and butterflies, making it a valuable addition to pollinator-friendly gardens. If you’re trying to create habitat for beneficial insects, this tree can play a supporting role in your efforts.

Growing Casia Amarilla Successfully

The good news is that once you’ve determined your climate is suitable, casia amarilla is relatively straightforward to grow. Here’s what this tropical beauty needs to thrive:

Light and Location

Full sun is non-negotiable for the best flowering display. While the tree might tolerate some light shade, you’ll get fewer flowers and potentially leggy growth. Choose a spot where it can bask in sunshine most of the day.

Soil Requirements

Well-draining soil is crucial – this tree doesn’t appreciate wet feet. It’s fairly adaptable to different soil types as long as water doesn’t sit around the roots. If you’re dealing with heavy clay, consider improving drainage before planting.

Watering Wisdom

Young trees will need regular watering to establish a strong root system, but once mature, casia amarilla becomes quite drought-tolerant. This makes it an excellent choice for water-wise landscapes in appropriate climates.

Maintenance and Care

This is where casia amarilla really shines as a low-maintenance option. It typically requires minimal pruning – just remove any dead or crossing branches to maintain a healthy structure. The tree has a naturally attractive form, so heavy pruning usually isn’t necessary.

A Word About Alternatives

While casia amarilla can be a beautiful addition to warm-climate gardens, it’s worth considering native alternatives that might provide similar aesthetic appeal while supporting local ecosystems more effectively. Depending on your region, native flowering trees like Palo Verde (Southwest), Redbud species, or native Cassia species might offer comparable beauty with greater ecological benefits.

The Bottom Line

Casia amarilla is a stunning ornamental tree that can add tropical flair and golden beauty to the right garden. If you live in a consistently warm climate, have space for a medium to large tree, and want something that’s both beautiful and relatively low-maintenance, it could be an excellent choice. Just remember that this is a commitment – make sure you have the right conditions and enough space for this tree to reach its full potential.

The key to success with any non-native plant is understanding its needs and limitations. Casia amarilla rewards gardeners who can provide the warm, sunny conditions it craves with years of spectacular golden blooms that light up the landscape.

Casia Amarilla

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Rosidae

Order

Fabales

Family

Fabaceae Lindl. - Pea family

Genus

Senna Mill. - senna

Species

Senna spectabilis (DC.) Irwin & Barneby - casia amarilla

Plant data source: USDA, NRCS 2025. The PLANTS Database. https://plants.usda.gov,. 2/25/2025. National Plant Data Team, Greensboro, NC USA