CHAPTER IX

TREES AND SHRUBS WITH BEAUTIFUL CATKINS

When thinking of trees and shrubs in early spring we must remember those with beautiful catkins. Of the earliest flowering hardy trees and shrubs the majority are those with flowers borne in catkins. Their appearance is one of the first evidences of the approach of spring. It is to the catkin-bearing group that the Poplars, Willows, Birches, and Alders belong. These catkins are pendulous, cylindrical, and often slender inflorescences, carrying flowers of one sex only, which spring from the axils of scaly bracts. Being mainly dependent upon the wind for their fertilisation, they have none of the varied or bright colours that are characteristic of flowers fertilised by insect agency. Often, indeed, sepals and petals are entirely absent. Still, many of these catkin-bearers possess a charm and beauty of their own, which, taken with the early, often inclement, season when they appear, make the best of them indispensable in gardens where early spring effects are desired. As a rule it is the male or pollen-bearing catkins that are most ornamental. They are longer and more graceful than the seed-bearing ones.

POPLARS

First among Poplars to bear its flowers, and almost before winter is past, is the Aspen (_Populus tremula_). This and its weeping variety bear their catkins in February, but closely following it, and perhaps more ornamental, is the American Aspen (_P. tremuloides_). This species flowers early in March near London in mild seasons, but later further north, and when kept back by severe weather. The pendulous variety of _P. tremuloides_--known commonly as Parasol de St. Julien--is, at the flowering time, probably the most beautiful and striking of all catkin-bearing trees. This and also the type produce long, slender catkins that sway gently in the softest winds. The weeping variety, which has branches that weep naturally low, looks well by itself on a lawn. In all these Poplars the male catkins are three inches to four inches long, chiefly grey-brown in colour; the scale-like bracts, however, are suffused with a reddish shade. The weeping varieties of these two Aspens are frequently grafted on the White Poplar, which is not a suitable stock. The species to which the varieties severally belong should be used for the purpose. It would be even better if they could be got on their own roots by means of layers or cuttings, and trained up to the required height before allowing the weeping habit to develop.

There are other Poplars that bear their catkins freely, such as _P. alba_, _nigra_, and _balsamifera_, but being of loftier habit they do not show to the same advantage as those of the Aspen group.

HAZELS

Between the middle and the end of February the flowers on the catkins of the various species of _Corylus_ begin to expand. Early as that date is, the catkins have, nevertheless, been in evidence since the previous autumn; they were, in fact, formed before the nuts fell. Being comparatively low and shrubby the different varieties of the Hazel (_Corylus Avellana_) show their catkins to best advantage, and there are few among the catkin-bearers more charming. It is not often that any but the coloured-leaved varieties find a place in the garden proper, but either in the orchard or in the woodland the soft yellow of the Hazel catkins is one of the most pleasing notes of earliest spring. The Tree Hazel (_Corylus Colurna_), a fine and interesting tree, growing thirty feet or more high, also bears its catkins in February.

WILLOWS

Of the almost innumerable species and varieties of _Salix_, it is only a few that need be mentioned here for their beauty when in flower. So far as I have been able to judge, the most ornamental of the Willows in catkin time is _Salix smithiana_, known also as _S. mollissima_. This tree flowers about mid-March, producing its shortish, thick male catkins in very great abundance; the numerous exposed anthers give a soft but glowing yellow tone to the tree, and entitle it to rank as one of the most ornamental of early-flowering trees. The pendulous variety of _Salix Capræa_ is known as the Kilmarnock Willow. Although of weeping habit it is somewhat stiff in character; but towards the end of March and later it is exceedingly pretty loaded with its grey catkins. The flowers of the typical _S. Capræa_ (the Goat Willow) are commonly known in many country places as Palm, and are used for decorating churches on Palm Sunday. The slender, coloured twigs of the Purple Willow (_Salix purpurea_) bear red or purplish-tinted catkins in early April. _Salix stipularis_ may also be mentioned for its beauty when in flower.

ALDERS

With the exception of a few species, such as _Alnus nitida_ and _A. maritima_, which flower in September and October, all the Alders develop their blossoms in February and March. The common Alder (_A. glutinosa_) and its varieties are perhaps as ornamental as any at that time. Like the Willows, they look best and grow best in association with water. In such a position an Alder at that time, leafless, but laden with its slender, greenish-yellow catkins, is a beautiful object, and characteristic, too, of our English landscape. Other species possessing a similar quiet beauty are _Alnus incana_, _A. viridis_, _A. oregona_, and especially _A. cordifolia_ with its green and yellow catkins.

JAPANESE WALNUTS

_Juglans sieboldiana_ and its close allies, _J. mandschurica_ and _J. cordiformis_, do not flower till May, but bear at that time very remarkable male catkins. I have measured them over one foot long, and hanging as they do in goodly number from the branches, perfectly straight and cylindrical, they have a very striking appearance, although green. All three species are alike in their catkins, but differ in the shape of the nuts. They are noteworthy, too, for the imposing character of their foliage. The leaves are pinnate, and on young trees grown in good soil are frequently three feet long. They certainly deserve the notice of planters.

GARRYA ELLIPTICA

From all the catkin-bearers hitherto mentioned, this differs in being evergreen. It is also far removed from them in relationship, and is closely allied to the Cornels. At the same time the catkins in external characteristics are very similar. Not only the catkins but the plants themselves are unisexual, and, as is usual with the catkin-bearers, it is the male that is most ornamental. These catkins are from four inches to eight inches long, and I have heard of (but not seen) them as much as one foot in length. The time at which the flowers expand depends, as with all the early catkin-bearers, on the mildness of the season. This year on a wall the catkins have been in beauty ever since the first week of January. They are very attractive in their grace and quiet beauty. Chiefly of soft grey and green colours, the bracts are, however, suffused with a warmer reddish tint. In the neighbourhood of London Garrya elliptica is quite hardy in ordinarily sheltered positions, but does not flower so freely as against a south wall. As it is of Californian origin this is not surprising. This shrub resents disturbance at the root, and in transplanting great care is necessary.

There are other species of Garrya in cultivation, but they are more suitable to the south-western counties than to the average climate of Britain.

To the catkin-bearing family belong several other well-known trees, such as the Birches, Hornbeams, and Sweet Chestnut; but flowering later in the year their beauty is apt to pass without notice in the great flush of bloom that comes in with April. The beautifully fragrant Sweet Gale must not be passed without mention. Its reddish brown catkins are formed before autumn, and expand on the still leafless twigs in spring.