Iris grant duffii is similar in form to two of the North American species of iris, Iris tenax and Iris douglasiana.

It has seedlings, that grow a small rhizome bud that is between a tuber and a bulb.
At the first year of growth, the seedling bud is similar to a bulb of Iris reticulata.
Later, the bud forms a short, stubby rhizome.
 The rhizome is made up of bands of growth, each band created by a seasons growth.
Each growth band has remains of the leaves from the last season.
These are very spiny.
This makes holding the rhizomes very difficult and painful.
It is thought that these brown bristles/spines are formed to protect the plants from being grazed on by animals.

The creeping rhizome, eventually makes large clumps of plants.

It has greyish green leaves,(that are slightly glaucous), which grow up to between 35–70 cm (14–28 in) long,), and 5–10 mm wide.
There are up 6 leaves per stem, they are linear, flat and very clearly veined with a white margin along the edges.
They emerge in early winter and reach their full length after two months.

The iris has a stem (flowering stalk) that grows up to between 15–35 cm (6–14 in) tall.
The rounded, un-branched stems carry a single flower, which are slightly scented.
The base of the stem can be rather swollen and is encircled by a truncate scariose (dry brown) sheath.

The iris flowers between April and May in the UK, late spring In Europe, but within Israel, it is between February (on the coastal plains) and April (on the Golan Heights).
The flowers come in shades of yellow, from greenish yellow, yellow, to pale yellow.
They are dotted black or have purple or lilac veins (or streaks).
The flowers are generally 8 cm in diameter, with 6–7 cm long falls and 5–7 cm long standards.
The blade has an orange signal patch.

It has a 7mm long pale yellow perianth tube.
It also has yellow/pale yellow styles (part of the flower holding the stigma) which are 4.5 cm long.
The flower buds have green spathes which are paper-like.

The iris produces seed after the blooming period is over, in summer.
The seed capsules and cylindrical and ellipsoid and the seeds are red-brown, rounded and tuberculate.
Iris grant duffii is similar in form to two of the North American species of iris, Iris tenax and Iris douglasiana.
It has seedlings, that grow a small rhizome bud that is between a tuber and a bulb. At the first year of growth, the seedling bud is similar to a bulb of Iris reticulata. Later, the bud forms a short, stubby rhizome.  The rhizome is made up of bands of growth, each band created by a seasons growth. Each growth band has remains of the leaves from the last season. These are very spiny. This makes holding the rhizomes very difficult and painful. It is thought that these brown bristles/spines are formed to protect the plants from being grazed on by animals.
The creeping rhizome, eventually makes large clumps of plants.
It has greyish green leaves,(that are slightly glaucous), which grow up to between 35–70 cm (14–28 in) long,), and 5–10 mm wide. There are up 6 leaves per stem, they are linear, flat and very clearly veined with a white margin along the edges. They emerge in early winter and reach their full length after two months.
The iris has a stem (flowering stalk) that grows up to between 15–35 cm (6–14 in) tall. The rounded, un-branched stems carry a single flower, which are slightly scented. The base of the stem can be rather swollen and is encircled by a truncate scariose (dry brown) sheath.
The iris flowers between April and May in the UK, late spring In Europe, but within Israel, it is between February (on the coastal plains) and April (on the Golan Heights). The flowers come in shades of yellow, from greenish yellow, yellow, to pale yellow. They are dotted black or have purple or lilac veins (or streaks). The flowers are generally 8 cm in diameter, with 6–7 cm long falls and 5–7 cm long standards. The blade has an orange signal patch.
It has a 7mm long pale yellow perianth tube. It also has yellow/pale yellow styles (part of the flower holding the stigma) which are 4.5 cm long. The flower buds have green spathes which are paper-like.
The iris produces seed after the blooming period is over, in summer. The seed capsules and cylindrical and ellipsoid and the seeds are red-brown, rounded and tuberculate.
Iris grant-duffii