This without doubt in many peoples opinion is the ‘daddy of them all’ and must rate in the top varieties of Jasminum sambac available and indeed rates highly with the individual species as well.
Much material has been mislabelled and simple double forms are often offered under this name.

The true Grand Duke of Tuscany is indeed a grand sight to behold and offers all the very best of any tender ornamental plant. It has a tight compact form and is certainly more bush like and has few scandent tendencies apart from the occasional stout medium length stems it may grow.
It is easily kept tidy and will flower for about 8-9 months of the year in N Europe under glass with a break/rest in mid winter during the very shortest days. Its main flowering period being May till September, peaking in the middle or late summer and the odd single flowers opening at other times. It is ideally suited for the small container in part due to its very slow rate of growth.

Of all the Jasminum sambac varieties; none of which are very fast, this variety is the slowest and makes it ideally suited to a small container. A minimum temperature of about 5c/41f is required if it is to retain its evergreen leaves but this small indulgence in luxury is well worth the cost. It repays handsomely in return flowering its little heart out. Its scent is often described as ‘heavenly’ or ‘intoxicating’ and no amount of superlatives can do it justice.
It is heavy, rich and pungent and is one of the few Jasmines able to scent a conservatory and be smelt at a distance under glass in N Europe; of course in the tropics this plant is even more remarkable in its powerful scent. In my personal professional opinion it has no other equal for scent.

The flowers are large by Jasminum standards and one inch in diameter being about the norm with both larger and smaller being produced. Regarding appearance it is to my mind resembles a carnation or even a tightly grown ornamental cabbage in structure with many layers of tightly packed petals.

The flower changes form in quite an interesting way with the buds being swollen day by day like small almost perfectly round white balls and then bursts opens into a tightly packed flat topped flower often in the shape of a pumpkin.
As the days pass the whole flower becomes looser and the petals separate out and it becomes  bourbon rose like in appearance before finally falling. Often as the flower fades there is discoloration with the dull red/mauve colour tints to the old flowers. This possibly maybe due to either humidity/moisture or low light but is nothing to write home about.

The foliage often has slightly wavy leaf edges which to the trained eye can distinguish it from other species when not in flower along with the leaf nodes being closer together than most other sambac varieties.

This plant is easily grown and tougher than imagined and will often shoot from the base if frosted however this should be avoided because although the plant will survive and re-flower the leaves once dropped will be very slow to regenerate on the lower portion of the plant and the ‘palm tree’ effect is not to be encouraged.
A more serious frost will kill the wood back to the base and in a way is easier to regenerate from basal shoots that are quick to arise once spring and summer arrive. We have experience of both large and small plants having survived -5c for several nights but losses run at about 30%.
Nice thick stems become woody at the base and an annual shortening by 1/3 seems to produce a most attractive specimen.
The bigger the plant the more the flowers and here more than with most species, feeding pay real dividends.