Time to give tree lupins a try

The tree lupin does not really qualify to be called a “tree”, because it is more of a bush and only reaches a couple of metres tall and wide. The term tree is used by comparison with ordinary herbaceous lupins.

These have soft, fleshy stems, while the tree lupin has some woody development in the shoots. Even then the amount of woody tissue is not very great and the stems are quite easily broken.

However, despite not being the “tree” it is supposed to be, it is still a most dramatic shrub in full flower, the whole bush covered with spikes of pale lemon-yellow flowers. The flower spikes are smaller than those of the herbaceous lupin but they are carried in much greater numbers.

A traditional plant of cottage gardens in coastal areas, it produces lots of seeds, and self-sown seedlings pop up readily close to the parent plant. It was an easy matter to lift seedlings and give them, or the seeds, to friends and neighbours.

The seeds also act as an insurance against severe frost damage. The plant is not fully hardy. It is fine in most winters by the coast and survives inland in mild winters, but eventually gets caught. That is where the seed survival comes into play.

Survival routine

In the late spring or early summer, seedlings appear – and this can happen two or more years after the original plant was lost. This is the plant’s evolved survival routine, and it works very well, because it is generally necessary to plant it only once – although the plant can be lost, it revives itself.

To complement the pale yellow flowers, the grey-green foliage offers a perfect foil. The surface of the leaves has tiny white hairs that protect against wind and sea salt in coastal areas, and bright sunshine in its native California. The leaves are made up of about 10 leaflets, arranged like the fingers of a hand, in a typical lupin shape. The leaves are generally smaller than those of the herbaceous lupin.

The plant grown in gardens is identical with the wild tree lupin of its home territory. Blue-coloured forms exist there and are occasionally seen here too. There is a blue-purple form called ‘Mauve Queen’, and another with white flowers called ‘Snow Queen’, but these are not often seen, though seeds can be got online.

Tree lupin is a fast grower, making a nice plant in two or three years but, as shrubs go, it is not long-lived. Apart from frost damage, the bush itself often gets worn out from massive seed production, or it gets rocked in the soil by strong winds. When a root or two breaks, it usually fizzles out, to be replaced by its seedlings. In natural conditions, it is an early coloniser of disturbed ground, especially sandy areas by the coast and by river beds. A bush in full flower is a fine sight and looks really well in a country garden, particularly near the sea.

The flowers are sweetly scented and the scent travels in the air on a warm summer evening. When choosing a spot to plant, ensure full sunlight and well-drained soil, ideally sandy and not too fertile. Rich soil tends to make the bush very leafy and soft, prone to wind damage. Watch for signs of lupin aphid greenfly in early May, and control this pest if it begins to build numbers, because it can cause the loss of all the flowers in a short time.

Pak choi is Chinese vegetable related to cabbage – at least it is in the same family. It is generally used in stir-fries and steamed. It can be tricky to grow because of the variability of the summer weather. It likes heat and moisture and can run to flower quickly if these are out of balance.

Usually it gets easier to grow pak choi after mid-summer. A very fast-developing crop, the trick is to just sow a few seeds at a time. Then if they run to seed, all is not lost and there will be other sowings to follow.

It is easier to raise plants in celltrays than directly in the open ground, transplanting the seedlings when still quite small and well before the limited root run of the cell tray begins to restrict their growth.

Flowers

Flower beds and borders are looking well after weeks of good growth with mixed sunshine and showers. Containers of all kinds will need frequent watering, perhaps each day if the weather is hot. Make sure the pots do not dry out at any stage, because the plants can get a severe setback. Feeding should be given too, as often as once a week, and remember that feeding increases watering needs.

Lawns

Lawns are generally looking well, as good growth followed once the cool dull weather of late spring lifted. A lawn that looks tired needs a feed with high-nitrogen fertiliser but be careful not to overdo the feeding or the lawn can grow too fast – or worse, get scorched in dry weather. Trim the edges of a lawn to keep it tidy now that the grasses have shot out and flowered.

Trees, shrubs and roses

Roses have suffered plenty of blackspot disease, with wet days interspersed with sunshine. Soil moisture has been adequate to keep young trees growing, but check new plants. It is time to clip hedges of all kinds before the wood gets tough. Most hedges have grown very rapidly in recent weather. Any heavy cutting back should be left until the start of the growing season next year.

Greenhouse and house plants

Pot up house plants during the good growing period, to allow them to settle before winter. Continue watering and feeding greenhouse plants. Take cuttings of all kinds – especially shrubs, roses and clematis – now. Be careful to water plants in pots or grow-bags regularly. These can easily dry out. Train and side-shoot tomatoes and cucumbers. Watch for red spider mite.

Fruit, vegetables and herbs

Make some late sowings of lettuce, rocket and radishes. Watch for potato blight and control should be kept up, especially for maincrop potatoes. Remove vegetables that have gone over because of the warm weather. There has been good growth recently of sweetcorn, which likes sunny weather. If the soil is dry, peas and cabbages should be watered to keep the plants growing.