UNITED STATES—Many of us who are still sowing spring seed know the doubt. Seed for warm season vegetables and bedding plants is presently scarce. Consequently, we doubt that all the varieties that we want are still available. Many unusual varieties that we purchase by mail order or online are sold out. Some more popular and reliably obtainable varieties in supermarket seed racks are going fast too.

Home gardening is very suddenly more popular than it had been for a very long time. Those who cannot work at their respective professions have much more time to work in their gardens. Many want to grow a bit more produce at home, in order to shop amongst others in supermarkets less frequently. Many who have never enjoyed gardening before are now taking a serious interest in it.

Gardening just got a bit more competitive.

This adds a few more complications to planning the garden. Choices really are limited. Some of us must be satisfied with what we get. Instead of trying new and unusual varieties, we might need to try old and common varieties. It might be a new and unusual experience. It could also be an interesting way to learn why they have been so popular for so long. This applies to young plants as well as seed.

Although more varieties are available online and by mail order, it is now more important to purchase them early. Delivery is not as prompt as it was prior to this increase in popularity of gardening. Seed providers are overwhelmed by the demand. Since it is already late in the season, it is probably too late to order seed that start in spring. It is not too early to start procuring seed for autumn.

It is also a good time to share surplus with friends and neighbors who may be experiencing the same scarcity of seed and seedlings. Although it is too late to wait for delayed delivery of seed that gets sown in spring, it is not too late to sow some types if they are already available. If left outside to avoid personal interaction with recipients, seed might need protection from rodents and birds.

Anyone who is experienced with gardening knows that it involves challenges. This is certainly a new one.

Highlight: Mediterranean spurge

Seed for this species is all or nothing. The straight species of Mediterranean spurge, Euphorbia characias, seeds abundantly. It can actually be a bit too prolific. However, fancier and extensively bred cultivars either produce no viable seed, or produce only a few seed that are not true to type. Such seed grows into plants that resemble their ancestral species more than their direct parents.

Foliage of common Mediterranean spurge is slightly grayish green. Cultivars exhibit more distinctly grayish, bluish, yellowish or variegated foliage. Appealingly weird and generally greenish floral trusses bloom on top of upwardly arching stems about now. Mature plants are less than four feet tall and broad, with neatly rounded form. They slowly lean toward sunlight as they grow and bloom.

After old stems get cut to the ground in autumn, new stems develop through winter, to repeat the process. Established plants are surprisingly resilient to harsh exposure, warmth, wind and lapses of irrigation. They just dislike shade and constant dampness. However, even the healthiest live for only five to eight years. Those that toss seed can provide their own replacements before they go.

Horticulturist Tony Tomeo can be contacted at tonytomeo.com.