Actual size and flowering may vary slightly based on season.
Silvery Cassia
Silvery Cassia is an Australian evergreen shrub with flat, silver-gray, sickle-shaped leaves. From December through April it is covered in clusters of yellow flowers, and pollinators visit them. It grows about 5 to 8 feet tall and wide and needs little water once rooted. It is a popular desert shrub for mass plantings, borders and slopes.
Best for: silver foliage in mass plantings, borders and slopes, winter color, and pollinator-friendly desert yards on little water.
The flat, sickle-shaped leaves stay silver-gray all year. Planted 6 to 8 feet apart, it works in groups, in borders and on slopes.
Clusters of yellow flowers cover the plant from December through April. Bees and other pollinators visit the flowers.
Once it is rooted, it needs a deep soak only about once or twice a month in summer. Extra water just makes it bigger and leggier.
Too much water makes it leggy, and roots can rot in wet, poorly drained soil. Shearing cuts the bloom, so prune lightly right after flowering, which also removes the papery brown seed pods.
- Mass planting or slope6 ft apart
- Bed or border8 ft apart
Water every 3 to 4 days for the first two weeks. Then stretch it to every 6 to 7 days, then every 7 to 10 days, and every 10 to 14 days by about week 8.
Once rooted, give it a deep soak about once or twice a month in summer and less in winter. Too much water makes it leggy and yellow and can rot the roots.
Prune lightly right after it blooms to cut off the seed pods. Pruning later in the year removes next spring's flowers, and frequent shearing cuts the bloom.
Once it is rooted, it needs little or no fertilizer and little extra water. Too much water makes it grow leggy.
It handles cold to about 20°F. On a rare colder night, cover it with frost cloth that reaches the ground and take it off in the morning.
Drainage test first. Dig the hole and fill it with water. If water is still sitting in the hole a day later, you likely hit caliche, clay or hard soil, so fix the drainage before planting. If it drains very fast, the soil is sandy. Standing water around roots is a common reason new plants fail.
Weed cloth. Cut it away from the planting hole and where the roots will spread. Remove any plastic sheeting completely, since it keeps water and air out of the soil.
Rock or decomposed granite with no soil underneath. Bring in soil close in texture to your native soil, mix it with the soil below, and build up enough depth for roots before planting.
If you can break through. Use a breaker bar, pick, or jackhammer. Dig through the caliche and break out the solid chunks. Backfill with the soil you dug out, with no compost or manure in the hole. Confirm drainage before planting.
If you cannot break through. Dig narrow holes through the hard layer beside the root ball, not under it, and refill them with the same soil, not gravel. If it still will not drain, plant on a low mound of the same soil.
Root ball. Check the outside edges for any roots circling around. Loosen or cut those so they grow outward. Do not break up the center of the root ball.
Depth. The top of the root ball should sit at or just slightly above the surrounding soil level. Planting too deep can lead to rot and kill the plant.
Drip emitters. At planting, put the emitters on the root ball, on different sides of the plant. After about 2 months, move them to the outer edge of the root ball. Over the first year, add emitters farther out toward the edge of the branches as roots grow. Once a plant is rooted, never water only at the trunk.
Is Silvery Cassia the same as Silver Cassia or Senna phyllodinea?
Yes. It was sold as Cassia phyllodinea and is now named Senna phyllodinea. It is also called silver cassia or silver-leaf cassia.
How big does Silvery Cassia get?
It grows about 5 to 8 feet tall and wide, and extra water makes it larger and leggier. Water sparingly once rooted to keep it compact.
How far apart should I plant Silvery Cassia?
Plant it about 6 to 8 feet apart, center to center. Use 6 feet for a mass planting or slope and 8 feet in a bed or border.
When does Silvery Cassia bloom?
It blooms from December through April, when clusters of yellow flowers cover the plant and pollinators visit them. Save any pruning for right after the bloom.
Why are the leaves flat instead of feathery?
Its leaves are flat, silver-gray and sickle-shaped, not split into fine needles like Feathery Cassia. That is normal for this plant, and the silver color lasts all year.
What are the brown pods?
They are papery brown seed pods that follow the flowers, and a light trim right after bloom removes them.
When should I prune Silvery Cassia?
Prune it right after it finishes blooming, and do not shear it. A harder cut of up to about half after bloom renews an overgrown plant.
How often should I water Silvery Cassia?
Once rooted, give it a deep soak about once or twice a month in summer. Plant it in soil that drains well and let the soil dry between soaks.
How cold hardy is Silvery Cassia?
It is rated hardy to about 20°F. Cover young plants with frost cloth on the coldest nights.
How is it different from Feathery Cassia?
Silvery Cassia has flat, sickle-shaped silver leaves and blooms from December through April. Feathery Cassia has fine, needle-like gray leaves and fragrant flowers. Both need little water, so choose by the leaf look you prefer.
Silvery Cassia for sale in Arizona, delivered to you
Silvery Cassia, now named Senna phyllodinea, is an Australian shrub grown for its silver-gray leaves and long winter bloom. It flowers yellow from December through April, stays evergreen and needs little water once rooted. This page covers its size, spacing, bloom, seed pods, pruning and watering, and how it compares with Feathery Cassia.
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How big does Silvery Cassia get in Phoenix?
It grows about 5 to 8 feet tall and wide. Extra water pushes it larger and leggier, so water deeply but not often.
When does Silvery Cassia bloom?
It blooms from December through April with clusters of yellow flowers. Papery brown seed pods follow the flowers.
How far apart do you plant Silvery Cassia?
Plant them about 6 to 8 feet apart, center to center. That works for mass plantings, borders and slopes.
How often do you water Silvery Cassia?
Once it is rooted, give it a deep soak about once or twice a month in summer. It needs good drainage, and too much water makes it leggy.
When should you prune Silvery Cassia?
Prune right after bloom and do not shear it. A light trim removes the pods, and a harder cut of up to about half renews an old plant.
What is the difference between Silvery Cassia and Feathery Cassia?
Silvery Cassia has flat, sickle-shaped silver leaves. Feathery Cassia has fine, needle-like gray leaves and fragrant flowers. Both bloom yellow in winter and spring on little water.
We deliver across the Valley, from Phoenix, Scottsdale and Mesa out to San Tan Valley, Maricopa and Casa Grande, and up to Prescott, Sedona, Payson and Globe. See delivery areas and rates.